Preheat your oven to 350°F (175°C) and grease two 8-inch round cake pans. Line the bottoms with parchment paper.

In a large bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Beat on medium speed until well combined.

Slowly add the boiling water to the batter, mixing until smooth. The batter will be thin.

Divide the batter evenly between the prepared pans and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Let the cakes cool for 10 minutes in the pans, then transfer them to a wire rack to cool completely.

While the cakes cool, heat the heavy cream in a small saucepan until it just starts to simmer. Remove from heat and pour over the white chocolate chips in a heatproof bowl.

Let the mixture sit for 2 minutes, then stir until smooth to create a white chocolate ganache. Divide the ganache into separate bowls and tint each with a different gel food coloring (blue, purple, pink, black).

Level the cooled cakes if needed and stack them using a thin layer of ganache between the layers.

Prepare the mirror glaze according to the package instructions or recipe if making homemade. Divide the glaze into bowls and tint each with the same gel food coloring used for the ganache.

On a large baking sheet or cooling rack, place the stacked cake and pour alternating colors of the mirror glaze over the top, letting it drip naturally to create a galaxy effect.

Use a spatula or knife to lightly swirl the colors together for added dimension. Let the glaze set for 1-2 hours.

Serve the cake and enjoy the mesmerizing galaxy design!