Cook's Note: Make sure all of your ingredients are at room temperature.
Preheat your oven to 400 degrees F. Line 2 baking sheets with parchment paper.
Sift the flour, cocoa, baking soda, baking powder and salt together onto parchment paper. With an electric mixer on medium-high speed, cream the butter and sugars until light and fluffy, 4 or 5 minutes. Add your eggs, 1 at a time, mixing until completely incorporated before adding the other egg. Mix in the chocolate and vanilla, making sure to combine really well. Turn the mixer to low and slowly add the dry ingredients, alternating with the buttermilk, in 3 batches, starting and ending with the flour mixture. Make sure to let it mix thoroughly.
Heap the batter onto the baking sheets with a 1-ounce ice cream scoop. Bake until the tops crack, 12 to 15 minutes or so. Cool on a rack. Repeat with the remaining batter.
Spread 2 heaping tablespoons of Cream Cheese Filling onto half of the cakes. Sandwich together with the other cake halves. Refrigerate for 1 hour. Store in an airtight container in refrigerator for up to a week, and allow to come to room temperature 1 hour before serving.
Cream the cream cheese, butter, salt and almond extract in a mixer on low speed with the whisk attachment. Slowly add the confectioners' sugar and mix until smooth. Scrape down the sides and bottom of the bowl when necessary.;
Make sure all of your ingredients are at room temperature.