1. Preheat the oven to 350 degrees. Grease two 8-inch cake pans with gluten-free cooking spray or rub with coconut oil. Shake some extra cocoa powder on the inside of the pans and coat the whole pan with it. Set aside.
2. Combine the sugar, flour, xanthan (if using), cocoa, baking powder, baking soda, and salt in a large mixing bowl. Whisk to combine. Add the egg yolks, milk, oil and vanilla, and beat until smooth. Carefully whisk in the hot coffee. The batter will be runny.
3. Whisk the egg whites until fluffy and not runny. Gently fold into the cake batter until fully incorporated. This helps give the cake its fluffy spongy texture.
4. Evenly distribute the cake batter between the two prepared pans and bake for 30-35 minutes, or until a toothpick inserted in the middle of the cake comes out clean. Let it cool in the pans for 5 minutes, then turn out onto a rack to finish cooling completely.

For the Whipping Cream

1. Add the cream and sugar to a bowl and whisk until fluffy

For the Ganache

1. Put the chocolate chips in a large bowl.
2. Bring the heavy cream to a boil, then pour over the chocolate chips.
3. Allow to sit for 10 minutes, then whisk until smooth.
4. Let the ganache cool until it is still pourable but not hot and pour over cake. Store the excess in the refrigerator.