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ATK Kids

Make a Mirror Cake So Shiny You Can Almost See Yourself in It

Small-but-mighty gelatin is the secret to this supershiny cake.

Published Oct. 22, 2021.

Frosted layer cake is a classic for a reason: It’s perfect for any celebration, from a backyard bash to a lavish wedding. You can also design it to be as simple or intricate as you like. Our team at America’s Test Kitchen Kids, however, has come up with a cake that’s both easy to make and amazing to behold. Any kid can make it—it’s called a mirror cake.

So, how did we put the “mirror” in mirror cake? It’s all about the magic of gelatin. Thanks to this magical ingredient, you can transform the entire surface of your cake into a glimmeringly mirror-like, out-of-this-world masterpiece. (We’re not kidding when we say “out-of-this-world”—the glaze looks something like a far-off galaxy.)

Kids can learn even more about kitchen magic in our latest cookbook for young chefs, The Complete Cookbook for Young Scientists. Not only will they learn how gelatin creates the most fantastical cake but they’ll also figure out why onions make you cry, why corn pops, and so much more.

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Now, back to that gelatin. How does this powerhouse ingredient turn the glaze into an edible, reflective work of art?

When the gelatin in the glaze is above 50 degrees, it’s a pourable liquid. But when gelatin’s temperature drops below 50 degrees, it begins to turn solid. And the colder gelatin gets, the faster it solidifies—that’s why we freeze the frosted cake before pouring the glaze on top.

When the warm glaze hits the cold cake, its temperature drops and the gelatin starts to become a solid. As it cools, it traps the water inside a tangled mesh of gelatin molecules. After the glaze sets in the refrigerator for 20 minutes and its temperature reaches below 50 degrees, the water trapped inside this solid gel acts like a smooth, reflective pond, puddle, or mirror!

For a truly knockout mirror cake, keep a few things in mind.

  • You can make the glaze with either two or three colors of gel food coloring—do not substitute liquid food coloring.
  • While we love to use our Easy Chocolate Layer Cake with Vanilla Frosting for this recipe, you can also use boxed cake mix and store-bought frosting.
  • Make the smoothest base possible for the mirror glaze by following our instructions for how to frost a layer cake.
  • Strain the glaze through a fine-mesh strainer and stir it as it cools to ensure silky-smooth results.
  • Combine the food coloring as instructed in the recipe for a picture-perfect cake.

Hey! Did you know ATK Kids has its very own YouTube channel? Subscribe now and watch great, funny, silly, and delicious cooking videos for the whole family.

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