Clinton Kelly, host of Food Network's "Spring Baking Championship," shows how to make a viral mirror cake — and the key is getting the glaze right.
- Even though it might seem a bit fussy, using a thermometer is key here because the glaze has to be at 90° Fahrenheit when you pour it. If it's too hot, it will be too thin and run off the cake too much — and if it's too cold, it will be too stiff and won't coat the cake properly.
- With that said, even glaze that's at the perfect temperature will run off a bit, so don't worry about that.
- Place your cake on a cardboard cut-out the exact size of the cake. This will help the glaze run off the sides of the cake, instead of pooling on a plate.
- Set up a glaze-pouring station in advance: A rimmed baking sheet with a wire rack works well. When ready to pour, take the cake out of the freezer and set the cake on the cardboard cut-out on top of the wire rack.
- When tinting the glaze, make your colors slightly brighter than desired — they thin out when poured and become more subtle.
- 2 boxes yellow cake mix, prepared according to package directions
- Prepared white buttercream frosting
- Two ¼-ounce packets unflavored gelatin
- 1 cup water, at room temperature
- 1 ½ cups granulated sugar
- ⅔ cup sweetened condensed milk
- One 11-ounce bag white chocolate chips
- Gel food coloring, in desired colors
Level the yellow cake(s), then frost with a smooth, even layer of buttercream. While you prepare the glaze, freeze the cake for a minimum of 20 minutes.
For the mirror glaze, in a small bowl, bloom gelatin in ¼ cup room temperature water. Set aside.
In a small saucepan over medium heat, combine remaining ¾ cup water with sugar and sweetened condensed milk. Stir until sugar is dissolved completely; do not let the mixture boil. Turn off heat.
In a large bowl, microwave white chocolate chips for 30 seconds. Stir, then repeat until chips are melted.
Over medium-low heat, whisk the "bloomed" gelatin and melted white chocolate into the warm sugar mixture until smooth and combined to make the glaze.
For a single-color glaze, add enough gel food coloring to reach desired color. When the glaze cools to 90˚F on a digital thermometer, pour it over the chilled cake.
For a three-color design, separate the glaze into three bowls, keeping ⅓ in the original large bowl. Tint with gel food coloring as desired, then pour all three glazes back into the original bowl without mixing—they will create a swirled effect when poured. When the glaze cools to 90˚F on a digital thermometer, pour it over the chilled cake.
Once the glaze coats the cake and the excess runs off, return the cake to the refrigerator to set.