Preheat the oven to 350°F and grease 2 (two) 6-inch cake pans (see blog post for advice on baking in larger pans). Line the bottoms of the pans with parchment paper circles and lightly grease the parchment.
In a medium bowl, whisk together the almond flour, cocoa powder, protein powder, baking powder, espresso powder, and salt.
In a large bowl, beat the butter with the sweetener until well combined and fluffy, about 2 minutes. Beat in the eggs and vanilla extract until smooth and creamy.
Add the almond flour mixture in two additions, alternating with the coffee liqueur. Beat until just well combined, scraping down the sides of the bowl and the beaters as needed.
Divide the mixture evenly between the two baking pans, and bake 30 to 35 minutes, until risen and the tops are firm to the touch. Remove and let cool 30 minutes in the pans, then run a sharp knife around the edges and flip out onto a wire rack to cool completely.
Once the cakes have completely cooled, slice carefully through the middle of each with a serrated knife, to make 4 cake layers. Note: If your cakes are very domed at the top, carefully slice off the domes to even them out.
Gently warm the coffee liqueur in the microwave and stir in the espresso powder until dissolved. Let cool to room temperature.
In a large bowl, beat the mascarpone with ½ cup of the powdered sweetener until well combined. Beat in 2 tablespoons of the coffee mixture.
In another large bowl, beat the heavy cream with the remaining sweetener and the vanilla until it holds stiff peaks. Add the mascarpone mixture and beat on medium speed until just combined. Then beat in the remaining coffee mixture until the frosting holds stiff peaks.
Place one layer of the cake on a cake plate and top with about ½ cup of frosting, spreading to the edges. Repeat with the remaining cake layers and frosting.
Spread the remaining frosting over the sides of the cake, reserving a little for piping decorative accents, if desired.
Place coffee beans decoratively around the top of the cake and sprinkle with chocolate sprinkles.
Gently press some chocolate sprinkles into the base of the cake, all the way around.
To bake this cake in 8-inch round pans:
Prep the pans as directed above and divide the batter evenly between them. Bake at 350F for about 15 to 20 minutes. They will be much thinner than the 6 inch cakes.
Do not attempt to split the cakes in half, they will be much too thin and fragile. Frost as a 2 layer cake and enjoy!