Preheat oven to 350° F (177°C). Prepare four 8-inch round cake pans with parchment rounds, and grease the sides. Set aside.

In a large bowl, sift flour, both cocoas, salt, baking soda and baking powder. Whisk to combine, set aside.

In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar on medium speed until pale and fluffy, 4-5 minutes. Scrape down the sides and bottom of the bowl.

Lower the speed to medium-low and add eggs one at a time, mixing after each addition until just combined. Scrape down the sides and bottom of the bowl.

In a small bowl, combine the vanilla and instant coffee granules. Add the sour cream to the batter along with the vanilla coffee mixture and beat on medium speed until combined.

Combine the buttermilk and champagne in a liquid measuring cup or a large bowl. Set aside.

Alternately add ⅓ of the dry ingredients, then beat on medium-low until just combined. While the mixer is running, pour in ½ of the buttermilk mixture and mix until just combined. Repeat this process with ½ of the remaining dry ingredients, the other ½ of buttermilk, then the final amount of dry ingredients. Mix until completely combined.

Divide batter equally between the cake pans, a little over 2 cups per pan.

Bake two layers at a time for 20-25 minutes or until a toothpick inserted into the center comes out clean and cake springs back when lightly touched.

Remove cakes from oven and allow to cool in pans for about 10 minutes, then turn onto cooling racks to cool completely before frosting. Or at this point, you can wrap all the cake layers tightly in plastic wrap and freeze or refrigerate until ready to assemble.

In a medium mixing bowl with a hand-held mixer, beat the butter and salt on medium-high speed until light and fluffy (about 5-6 minutes).

Turn the mixer to low, and gradually add 3 cups of powdered sugar, one cup at a time.

Once incorporated, add champagne and beat on low until combined. Mixture will look curdled. That's normal.

Add the remaining 2 cups of powdered sugar one cup at a time and mix on low until combined.

Once the sugar is combined, increase mixer speed to high and whip until light and fluffy, about 5-7 minutes. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl with a hand-held mixer, beat the butter on medium speed until light and fluffy (about 5-6 minutes).

Turn the mixer to low, and gradually mix in half of the sugar one cup at a time. Mix in both cocoa powders.

Once incorporated, add heavy cream, vanilla and salt and beat until combined.

Add the remaining powdered sugar one cup at a time and mix on low until combined.

Once the sugar is combined, add the black gel food colouring. 2 tablespoons may sound like a lot, but it’ll give your frosting the deepest and darkest shade of black we want!

Increase mixer speed to high and whip until light and fluffy, about 5-7 minutes.

Combine your sprinkle variety in a medium bowl, see notes. Set aside.

Take 2 layers of cake and stack them on top of each other. Make sure they’re lined up perfectly.

Use a biscuit cutter (or even a tall glass) to cut a hole down the centre of both cakes. Save the excess cake for midnight snacking and set the layers aside.

Use an offset spatula to place a dollop of champagne frosting onto a cake board or serving platter that’s on a turntable. Place one whole cake layer on top and spread about 1 cup of the champagne frosting on top.

Place one of the cut out layers on top and spread frosting around the hole (not inside). Repeat with the second cut out cake layer and spread frosting on top of that.

Pour in your sprinkle mix until it reaches the top. You should have some leftover for decorating.

Place the final layer on top, upside down. Frost the entire cake with a thin layer of champagne frosting. Chill the cake for 30 minutes.

Remove cake from refrigerator and frost the entire cake with a thick layer of black buttercream. Transfer remaining buttercream to a piping bag fitted with a large star tip (I used Wilton 8B). Set aside.

This part is optional, so feel free to skip it. Dip a small food safe paintbrush into some edible gold paint, then flick it onto the cake to add gold splats. If you do this, cover the floor, counter and walls with something to catch the splats.

Pipe a rope border around the top of the cake. Pretty much just pipe in a barrel roll motion.

Pour some of the remaining sprinkles into the centre of the cake and around the bottom. Slice and serve!