To make the Chocolate Birthday Cake batter start by pre-heating the oven to 350ºF. Grease and line with parchment three 8-inch cake pans. Grease the parchment and the sides of the pan as well.

Alternatively you can use two 9-inch pans.

In a large mixing bowl, mix the flour, sugar, cocoa powder, baking powder, baking soda, salt, and espresso powder (if using). Whisk to combine.

In another bowl, combine the eggs, vegetable oil, buttermilk, sour cream, and the vanilla extract. Whisk until completely incorporated.

Pour the wet ingredients over the dry ingredients and whisk until combined. When the batter is incorporated, add the hot coffee and mix to combine.

Whisk until the batter is smooth. The chocolate cake batter will be very thin and liquidy.

I like to transfer it to a bowl with a spout to help distribute the cake batter between the cake pans, which helps with such a runny batter.

Divide the batter evenly between the cake pans.

Tap them gently against the counter to release any bubbles.

Bake the cakes in the oven for about 30 to 35 minutes, until a toothpick inserted into the cake comes off clean.

Let the cakes cool down for 15 minutes in the pan.

Then remove the cakes from the pan. Let them cool down. If you aren’t frosting the cake on the same day, I recommend you wrap each layer individually in plastic wrap and then freeze until you are ready to use the cake layers. When you are ready to frost the cake, you can simply use the frozen cake layers, or let them sit on the counter for 20 minutes before frosting the cake.

The syrup is optional, but really helps take the cake to an extra level of rich chocolate taste.

To make the syrup, add the sugar and cocoa powder to a saucepan and whisk to combine. Add the water and whisk again. Over medium heat, whisk the mixture until it comes to a boil and the cocoa powder has dissolved with the sugar and water.

Let the syrup cool down, then cover until you are ready to use. You may have to whisk the syrup again before using it to brush on the cake layers.

Place the chocolate chips or chopped chocolate in a bowl. Place in the microwave for 15 to 30 second intervals, stirring until melted.

Heat up the heavy cream gently, until just hot, and pour over the melted chocolate chips.

Let the mixture cool down for about 15 minutes.

Sift the powdered sugar and cocoa powder together.

In a large bowl, or the bowl of a stand mixer, beat the butter for 1 minute using the paddle attachment, until creamy.

Add the sifted powdered sugar and cocoa powder slowly, while beating the butter on low, scraping the bowl every so often to ensure everything is getting nicely incorporated together.

Add the cooled ganache (the melted chocolate and heavy cream) along with the vanilla to the bowl, and beat on low until combined.

Add the vanilla extract and mix.

To assemble the cake, start by placing one cake layer on a cake plate.

Brush the cake layer with the syrup, if using. Allow a couple of minutes for the cake to soak up the syrup.

Spread the Chocolate Buttercream Frosting on the cake layer. Use an offset spatula to smooth out the frosting.

Place another cake layer on top. Brush syrup on the cake layer.

Spread more Chocolate Buttercream on the cake layer, and smooth it out with an offset spatula.

Top it with the final cake layer, and also brush it with syrup.

Spread the frosting on top of the cake and all over the sides of the cake.

Use an offset spatula to smooth out the top of the cake.

And use a bench scraper to smooth out the sides of the cake.

To do the spiral look, grab a smaller offset spatula or a kitchen knife and place it on the side of the cake. Just the tip of the spatula is touching the cake. Spin the cake plate around as you move the spatula up the side of the cake, until you reach the top. Do the same for the top of the cake, place the tip of the spatula on the top edge of the cake and spin the cake plate around as you move the spatula to the center of the cake.

Top the cake with the sprinkles, you can also throw some sprinkles against the sides of the cake so they will stick to the sides while the frosting is still not dry.

Store the cake in the fridge for up to 4 days, in an air tight container. You can also wrap the cake in plastic and freeze it, for up to 2 months.