More than a recipe, you will learn my tips to make your very first galaxy mirror cake a success. Do I mention the planning is super important too? A suggested cake making timeline is attached.
Simple tips and tricks||Go straight to the recipe
Truth to be told. I had no idea how to bake before I arrived in the US a few years ago. I didn’t even have an oven in my apartment in China. During my years in Paris, I had a small toaster oven. You may think if I want to learn how to bake, I should learn it from French pastry chefs, right? But there were 3 bakeries on the same street where I lived, and each of them has their own specialties (Palmier, Napoléon, and Opéra are my favorites ). Why bother baking myself when we can buy warm baguettes and pain au chocolat around the corner every day?
I started baking because we miss those fresh out of oven baguettes (which cost 60 cents each at the time); because on special occasions, we want to be able to eat pretty desserts without swallowing some weird tasty frosting or overwhelmed by sweetness. For my other half, for my kids, and for friends, I started baking bread, making puff pastry, quiches, macarons, and cakes. Getting better with each baking experiment, now I even received encouragements to open a bakery. But I love being an amateur baker and enjoy all the perks that come with it.
The recipe is pretty straightforward. And there are many similar ones out there, even video tutorials. I recommend you to check out a few. They all made the whole mirror glaze making process seem super easy. I think I can add my 2 cents here, also some crucial information, and warn you about WHAT CAN GO WRONG.
- What kind of chocolate to use?
-Use chocolate callets, chocolate baking bars, or even better if you can find couverture chocolate (in form of disk, bar or block) that contain a higher percentage of cocoa butter, that will give more sheen and have a creamy mellow flavor. I used Ghirardelli White Chocolate Baking Bars that are available in most of the supermarkets. They worked out perfectly.
-DO NOT use candy melt or compound chocolate. Read the label, if there is no real cocoa butter in the ingredients, it is not real chocolate and you won’t achieve the same consistency.
-DO NOT use chocolate chips that are designed to keep their shapes even after baking. We need the chocolate that can melt easily.
- Measurement:
I measured the ingredients in grams and in cups, so the conversion has already been done for you. The best part is that you don’t need to use too many different measuring cups and bowls, and have to wash them later.
You may want to adjust recipe quantity according to cake size and shape, the number of colors you want to add to the glaze, and your pouring technique.
-Normally a wide and flat cake need less glaze than a tall cake like mine.
-To achieve a more colorful the cake you need more glaze. For example, for the same size cake, a red and white marble cake needs less glaze than this galaxy cake that used 5 colors. Better your pouring technique is, less glaze you’ll need.
-Better your pouring technique is, less glaze you’ll need. A large tall cake is more difficult to cover than a small and thin cake.
My advice for this particular recipe: make a little more glaze just to be safe, so you don’t risk having empty spots on your cake. This recipe has taken this into account. What if you have too much glaze left? You can make these small cake pops dipped in galaxy glaze.
- Prepare the buttercream covered cake.
Try to cover your cake with a buttercream outer as smooth as you can. Like fondant, a mirror glaze won’t hide any uneven spots on your cake, so take some time to get a nice smooth finish.
The buttercream cake needs to be very cold before you pouring on the mirror glaze. Chill in the fridge for at least 2 hours. You should be able to touch the cake without smearing the buttercream.
- Mix the food colors:
Control the color by mixing in the food colors a little bit at a time to reach your designed color. You can use a toothpick if you are using gel colors in a small jar that has a big opening. If you use good color in a squeezable bottle, the safest way to do is squeezing the color gel in a small separate bowl and add the amount you need to the food little by little. I cannot remember how many times that I squeezed too much food color and have to add other colors to achieve the right color, or have a muddy tone and have to start over.
A little trick to avoid somehow transparent mirror glaze is to add a tiny bit of white in your color mix to make the color opaque.
- What can go wrong?
I put the glazed cake in the home refrigerator overnight. The next morning a bump appeared right top of the cake, in the center. I was pretty panicked at the beginning, even want to use a fire torch to burn the bubble (a method recommended by a pro baker), but finally, I decided to leave it alone and maybe hide it with some sugar decoration later. But a few hours out of the fridge, this bump just magically disappeared. I haven’t been able to find any information why this happens. If you have a clue I would love to know.
When you move the glazed cake from your working station onto a serving plate or cake stand, it’s very likely the bottom edge is not smooth. Or if the cake is heavy like this one, you may touch the side of the cake and left a few ruined spots on the sides of the cake. But don’t worry you can use sugar pearls or other candy decoration to hide them. Nobody would ever know!
Day-3
Bake the cakes. This particular cake is a genoise cake. I used a double batch of my genoise cake recipe baked in two 7-inch cake pans.
After they cool completely, wrap them in plastic wrap and store them in your refrigerator. Cold cakes are less crumbly, easier to handle and trim.
Prepare your simple syrup. Mix one part sugar with one part hot water, until sugar has dissolved, leave it to cool on the counter. This 8-inch in diameter, 6-inch tall and 4-layer cake need about 1 1/2 cup of simple syrup. So you’ll need sugar and water, 3/4 cup each.
Day-2
Make your buttercream frosting. I like to use swiss meringue buttercream, or French buttercream (this cake need 4 batches of the recipe).
Trim a thin layer away from the top of the cakes, make sure the top is perfectly flat. You can use this cake leveler to guarantee a perfectly flat top. Then cut each 7-inch cake into 2 even layers. Brush or spray the simple syrup on each layer, add buttercream frosting, and crumb coat the cake. Chill it in the refrigerator.
Day-1
Add an outer layer of buttercream all around, take some time to achieve straight edges, flat top, and smooth finish.
Chill the cake overnight.
The day
Prepare your mirror glaze. Wait for it to cool down to about 90Fº, pour the glaze over the cake. Let the glaze drip for about half an hour, then move the cake to a serving platter or a cake stand, try not to touch the glaze on the side. If you do touch and left some minor indent on the cake, just use some sugar pearls to patch it up. Use a variety of color matching candies, gumballs or sugar pearls to cover the bottom edge of the cake to hide any imperfections.
It takes about 2 hours for me to make the glaze and finish decorating the cake. If you need more time or the party is in the morning, you can glaze the cake the night before. The cake is safe to be left on the counter for one night.
White Chocolate Mirror Glaze
Prep
Cook
Inactive
Total
Yield 4.5 cups
A straightforward white chocolate mirror glaze recipe.
You can add any food colorings to this glaze to decorate your dessert.
Ingredients
- 2.5 tbsp unflavored gelatin powder =19g
- 1/2cup cold water to bloom=100g
- 1.5 cup sugar=313 g
- 3/4 cup light corn syrup=259g
- 5/8 cup water =138g
- 3/4 cup sweetened condensed milk=230g
- 12oz white chocolate=340g (need to be real chocolate with cocoa butter, not candy melt, or chocolate chips), either in callets form or in tablet form (in the latter case need to be roughly chopped)
Instructions
- Add gelatin to 1/2 cup of cold water, mix it well and let it bloom for about 5 minutes.
- In a medium saucepan, whisk sugar, light corn syrup and 5/8 cup of water together. Turn the stove on medium high and cook about 8 minutes whisk often. Turn off the heat when it just about to boil. u
- Add gelatin to the pot, whisk until it has dissolved.
- Add condensed milk into the pot, whisk until well combined.
- Add white chocolate into the pot, make sure the liquid covers the chocolate, let it sit for about 2 minutes.
- Then use an immersion blender, blend everything smoothly. Then pass through a fine mesh strainer, the mirror glaze base is ready.
- Divide the glaze into different bowls, add different food coloring. Wait for the glaze to cool down to 90-95Fº (32-35Cº), and pour it over a well-chilled cake.
- For Galaxy cake you will need 1/2 of glaze to be dark blue, 1/4 to be navy, 1/8 of each electric blue, pink and purple.
Notes
This quantity will be enough to cover a cake of 6-inch tall, and 8 inches in diameter (that need a double batch batter of a standard 9-inch cake). There will be quite a bit leftover, but this is the safe amount to cover the whole cake, especially for the beginners. If you are confident, reduce the recipe to 2/3 quantity.
To cover a standard 9-inch cake, make about 1/2 of the recipe.
Courses Dessert
Hi. I’m planning to attempt this cake for my daughters bday… but I do not have an immersion blender. Is there something else I can use?
Any kind of blender would work, a Cuisinart food processor can work too. I used an immersion blender just because it’s easier to clean up. The objective is to have a lump-less liquid to pour over the cake, that’s how we get a smooth mirror-like glaze. The low tech way to achieve this is to use a strainer. I’m sure you can find one in your kitchen. Hope your cake will be successful! Happy birthday to our daughter!
Thank for making the process easy to understand. Can I make this cake a few days before the party? My daughter’s birthday is during the week (Thursday) and I want to make the cake on Sunday, how should I store it?
Hi Tesha,
Without saying, this kind of cake doesn’t do well in a warm environment (ex, on the kitchen counter). You can store it in the fridge for 2-3 days. But I recommend finishing icing the cake on Sunday but only glaze it the night before the event. The reason is that the glaze often takes moisture and odor from home refrigerators. There is a risk that your perfect mirror glaze will become cloudy.
I always crumb frost my cakes before buttercream, this locking in the crumbs. i am at a loss as to the purpose of the simple syrup.? I have done this cake before but am trying your version to see if I can get a better, smoother pour. I am curious as to the brand of colors you use. also is it drops, gel, soft gel paste, or just paste?
Hi Julie,
Yes, crumb coating is always necessary for a layerd cake. But the simple syrup has nothing to do with it. It is to make the cake layers moist. And it’s very common to add flavoring into a simple syrup, and sometimes flavored liquor (Amaretto, Cognac, Kahlua…). My favorite food coloring is AmeriColor gel food colors, which will retain their colors even after baking, for example, in macaroons. There are many variables in order to make a successful glaze, I think the most important is the temperature. The glaze needs to be 90-95Fº (32-35Cº), and the cake needs to be well-chilled before receiving the glaze. Hope this helps.
Thank you! i will get the colors brand you suggest – mine were just not vivid enough. I found the glaze poured so much better than my previous recipe and I will be using this for a wedding cake- She wants a mirror finish galaxy cake. Odd, I know, for a wedding but that is her theme in colors.
Two more questions. Have you ever added vanilla to the glaze? like maybe substitute a couple tsp of corn syrup with vanilla? We find it okay in taste but rather blah and a couple of my taste tester said it had a funny after taste.- It helps that it has the buttercream under it but just wondering about enhancing the taste. Also can you freeze leftover cake? This trial one I did is way too much for my husband and I to eat all at once and we have half the cake leftover after the BBQ we went to and no one to share it with. I want to freeze it in 2 slice sections so we can have it slowly over a few months. I know it works well with regular buttercream, just wonder about the glaze..
Hi Julie, I’m glad to hear that you found my glaze pouring better. I would clarify that the corn syrup is for the consistency of the glaze, not the taste. I would not recommend substituting any amount of corn syrup (a form of sugar) for vanilla abstract (a form of alcohol with vanilla flavor). I would recommend adding flavor in the simple syrup, you will have a more pronounced vanilla taste in the cake and it will be moist and tender. My guests and I haven’t discovered any unpleasant taste in the glaze. If you are experiencing funny after tastes, maybe double-check all the ingredients you used to make it. Do some of them have a weird smell or taste? Is it quality chocolate? Has anything passed the best-by-date? Etc……Sometimes food coloring can have a strong taste, especially in big quantities.
For the freezing part, I personally have never tried to freeze the cake with a glaze. I imagine that the buttercream cake would be fine, but the glaze may crack and absorb odor from the freezor. If you do freeze your cake, I would like to know how it turns out, form and taste-wise. Happy baking!
hi! I am getting ready to make the wedding cake next week (the 14th Of August) I mentioned previously. As I look at the pictures you have, I am wondering hoe you got the tiny white flecks that make it look like stars. Is that white edible glitter or did you “fleck” it from a brush of white glaze ?(I would be afraid of doing that I think, this being a wedding. as I would not want clumps…) I like the look of the stars, but I would not do the long streaks I think. So seeking the method to make those stars.
If I recall correctly, I think I may have spattered some glaze tinted with white food coloring. If you wish to have more control, I suggest using golden or silver star sprinkles, which give a pretty festive look. Wilton has quite a selection of those. Wish you great success making this wedding cake!
Well I tried it for the first time, very sticky. How is it to cut?
You can use wire cheese cutter or even dental floss to cut the cake.