Preheat the oven to 350 degrees F (175 degrees C). Generously grease an 8-inch cake pan with butter, and place a round piece of parchment paper in the bottom. Dust the inside and sides with cocoa powder and knock out excess. Set aside.

Place chocolate and butter in a mixing bowl, and place on top of a saucepan filled with 1 inch of water. Place on low heat until the butter and chocolate have melted.

Remove from heat, and stir together with a spatula. Stir in almond meal, cocoa powder, coffee liqueur, salt, and cayenne until fully combined. Set aside.

Combine eggs and sugar in a second bowl, and beat with an electric mixer, or whisk by hand until very thick and pale colored.

Pour chocolate mixture into the egg mixture; fold in gently with a spatula until just combined. Transfer batter into the prepared pan. Tap pan on the counter to settle the mixture.

Bake in the preheated oven until a wooden skewer inserted near the center comes out almost clean, 25 to 30 minutes.

Let cool for 30 minutes in the pan before turning out onto a plate. Let cool to room temperature, before wrapping and transferring into the fridge to chill before serving.