Preheat the oven to 350°F and grease and flour three 6-inch round cake pans.
In a medium bowl, sift together the flour, baking soda and powder. Set aside.
In a medium bowl whisk together the egg whites, vanilla, vinegar, and color. Set aside.
In a microwave-safe bowl, melt the butter in a microwave for 20 – 30 seconds. Add the sugar and cocoa powder and stir until smooth. Transfer to a large bowl.
To the butter mixture, alternate the flour and liquid mixture.
Divide the batter evenly between the prepared pans (no more than ½ full). Bake for 20 – 22 minutes, until a toothpick inserted in the center comes out clean. Allow to cool in the pans for 10 minutes. Run a thin knife or offset spatula along the side of the cake. Invert the pans and remove the cakes from the pans. Transfer cakes to a cooling rack to cool completely.
Espresso Filling
Add chocolate and coffee/espresso to a medium glass bowl. In a small sauce pan heat cream over medium heat until right before boiling. Pour hot cream over chocolate and let sit for 5 minutes. Whisk until smooth. If small specks of chocolate remain, heat in the microwave for 20 seconds at a time, whisking in between, until smooth.
Cream Cheese Frosting
Using a stand mixer or a hand mixer, beat together the cream cheese and butter until smooth.
Add the vanilla and beat until combined. Slowly add the sugar and beat until smooth. Add the salt to taste and beat until smooth.