2tspinstant espresso powder or instant coffee, optional(not regular ground coffee)
¾cupcold heavy whipping cream
Preheat the oven to 325 F, and position a rack in the center of the oven. Lightly spray an 8-inch springform pan with a removable bottom with non-stick baking spray.
Using a double boiler, melt the chocolate and butter, then stir together until smooth.
Meanwhile, combine the eggs, sugar and vanilla in a bowl. Use an electric mixer to beat the egg mixture on medium speed for 5 minutes. It will increase in volume and become lighter in color.
Whisk the melted butter and chocolate into the whipped egg mixture until smooth.
Sift the cocoa powder and espresso powder over the batter and whisk until smooth. Pour the batter into the pan.
Bake the cake for 25 minutes. The cake will puff up quite a bit, with a crackly surface on top. Set the pan on a cooling rack. Immediately run a knife around the side to loosen the cake from the pan, but leave the cake in the pan.
As the cake cools, it will settle back down and will not look nearly as puffed as when you first took it out of the oven. This is completely normal and is nothing to worry about. If the edges are higher, you can just gently press them down a bit so the cake is the same thickness across.Cool for 2-3 hours before serving.
Whip the cream, bourbon, vanilla and powdered sugar with an electric mixer until soft, fluffy peaks form.
Remove the sides of the pan, and cut the cooled cake into 8 pieces. The surface will be crackly, with a very moist, soft and fudgy texture underneath.
Serve each slice of cake with the whipped cream.
Leftover cake should be stored in an airtight container at room temperature, for 3 days.If the whipped cream deflates after being stored in the refrigerator, just re-whip it for a minute or two to serve with the leftover cake.