Preheat your oven to 350°F (175°C). Grease your chosen cake pan and set aside.
In a large mixing bowl, whisk together the sifted flour, cocoa powder, baking powder, baking soda, salt, and sugar until well combined and flour is light and airy.
Add eggs, milk, vegetable oil, and vanilla extract to the dry mixture. Whisk everything together until the batter is smooth and has no lumps, about 2 minutes. It’ll be quite thick but well combined.
Carefully pour in boiling water while mixing on low speed or gently folding, until the batter is thin and glossy—this helps create a moist texture.
Stir in the dark chocolate chips to add rich pockets of melted chocolate throughout the crumb.
Pour the batter into your prepared cake pan, smoothing the surface with an offset spatula for an even layer.
Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean. The cake will smell rich and chocolatey and will be slightly domed on top.
Remove the cake from the oven and let it cool in the pan for 15 minutes. Then transfer it to a cooling rack and allow it to cool completely before decorating.
Prepare your galaxy frosting: in a bowl, mix edible glitter into a generous amount of dark frosting or ganache, creating swirling patterns that mimic a starry sky.
Spread a thin layer of frosting over the cooled cake to seal crumbs, then generously coat the entire surface. Use a spatula or piping bag to swirl the shimmer across the top, creating a galaxy effect with sparkling specks.
Once the decoration is complete, admire the shimmering, swirling cosmos on your cake—then slice to reveal the moist, chocolate interior flecked with glossy chocolate chips. Enjoy this celestial treat!
