Preheat the oven to 350°. Line the bottom of two 9-inch (or 8-inch) cake pans with parchment paper, grease, and flour the sides. 

Sift the flour, cocoa, and salt into a small bowl and set aside.

Place the butter into a medium-sized bowl and zap it in the microwave until it melts. Stir in the vanilla. Set the melted butter aside while you whip the eggs. 

Beat the eggs with the sugar for 8 to 10 minutes until they are light and fluffy and tripled in volume. This is an important step to make sure the cake is tall and has a light texture. The whipped eggs act as the only leavening for the cake.

Sift half of the flour mixture over the egg batter and gently fold it in with a wide spatula. Repeat with the other half of the flour mixture.

Transfer 1 cup of the batter into the bowl with the melted butter. Whisk to combine well then pour back into the large bowl of batter. Use a large spatula to gently fold the batter until well combined.

Pour the batter into the cake pans and bake for 30 to 35 minutes. Don't open the door of the oven for the first 20 minutes of the baking time. The cake should start to shrink away from the sides of the pan when it is finished cooking. 

Let the cakes cool in the cake pans for 5 to 10 minutes then run a knife around the edge of the pans to loosen the cakes from the pans. Invert the cakes onto a cooling rack and remove the parchment paper.

Place the sugar, water, and liquor (or non-alcoholic choice) in a saucepan and bring it to a rolling boil for 1 to 2 minutes. 

Set aside and let the syrup cool down to room temperature.

Chop the chocolate finely and place it in a bowl. The finer you chop the chocolate, the quicker and easier it will melt. 

Place the cream in a saucepan and bring it to a gentle simmer over medium heat or heat it in the microwave. Do not let the cream come to a hard boil. 

Pour the hot cream over the chopped chocolate and let it sit for 3 to 5 minutes to melt the chocolate. 

Stir until smooth. Set aside to cool slightly. 

Trim the top crust off each of the cake layers. If you want to make a four-layer cake, slice each layer in half horizontally. 

Place the cakes on some parchment paper and drizzle the simple syrup over each layer. You can use up to 3/4 cup of syrup in each cake (6 tablespoons per layer if you slice the cakes in half).

When you soak the sponge cakes, they tend to be prone to splitting when you transfer them. Slide a thin plastic cutting board under the cakes to transfer them easily. 

Place one cake layer on a cake board and top it with your choice of cake filling. Place the remaining layer on top of the filling.

If you want to cover the cake in the chocolate ganache glaze, transfer the cake to a rack set over a baking tray. 

Pour the ganache over the cake, letting it cascade over the edges and fall off into the baking tray. If there are any areas that did not get covered by the ganache, scoop up the ganache that fell into the baking tray and use it again. 

If the ganache sits too long and gets too thick to pour, you can heat it very gently in the microwave in 2-second bursts. It will thin out very quickly.