Galaxy mirror glazed box cake

Ingredients
for 10 servings

CAKE VANILLA BUTTERCREAM GALAXY MIRROR GLAZE FOOD COLORING
 * 2 chocolate cake mixes, 2 boxes, prepared according to package
 * 2 cups butter(460 g), softened
 * 2 teaspoons vanilla
 * 1 tablespoon milk
 * 6 cups powdered sugar(720 g)
 * 1 ¼ cups water(300 mL)
 * 1 ½ cups sugar(300 g)
 * 15 oz sweetened condensed milk(395 g), 1 can
 * 15 sheets gelatin
 * 26 oz white chocolate(740 g), chopped, over 30% cocoa butter
 * black food coloring
 * navy blue food coloring
 * light blue food coloring
 * purple food coloring
 * pink food coloring
 * white food coloring

Preparation

 * 1) Prepare the cakes according to the package, or use your favorite cake recipe.
 * 2) To make the buttercream, mix the butter, vanilla, milk, and powdered sugar in a bowl with a hand mixer.
 * 3) Once the cakes are baked and cooled, place one cake on a turntable. If you don't have one, you can use a plate. Slice the top off the cakes to create a flat surface.
 * 4) Place a large dollop of the buttercream on the cake and spread to create an even middle layer of frosting.
 * 5) Place the second cake over the layer of buttercream.
 * 6) Frost the entire cake to create the crumb layer, creating a smooth surface.
 * 7) Place the cake in the freezer to keep cold.
 * 8) For the glaze, boil the water, sugar, and condensed milk in a pot for 1 minute, then remove from heat.
 * 9) Bloom the gelatin in 8 cups (2 liters) of cold water for 5 minutes, then wring the gelatin sheets of excess water and mix into the sugar mixture.
 * 10) Pour the sugar mixture over the chocolate, letting it sit for 2-3 minutes to allow the chocolate to soften.
 * 11) Using an immersion blender, carefully blend the chocolate and the liquid, making sure that you are not blending in air bubbles by lifting up the blender too high.
 * 12) Pour the glaze through a sieve into a large bowl to remove any excess bubbles.
 * 13) Separate the glaze into 5 different bowls (one medium-sized bowl and four smaller bowls).
 * 14) Color the biggest bowl of glaze with black and navy blue food coloring, stir the coloring with the glaze until the color is distributed evenly.
 * 15) In the next bowl, add the navy blue food coloring and stir.
 * 16) In the next bowl, add the lighter blue food coloring and stir.
 * 17) In the next bowl, add the purple food coloring and stir.
 * 18) In the next bowl, add the pink food coloring and stir.
 * 19) When you are ready to use the glaze, make sure each one is around 90-96°F (32-35°C). Microwave if necessary. Pour the colored glazes back into the biggest bowl of black and blue glaze. Swirl them gently with a spoon.
 * 20) Place the cake on a stand over a sheet tray to catch any excess glaze. Carefully pour the glaze over the cake.
 * 21) Dip a brush into the white food coloring and fling it onto the cake to create stars.
 * 22) Enjoy!