Step 1

Preheat the oven to 350°F. Lightly grease a light colored 8-inch round 3-inch deep cake pan with nonstick cooking spray.* Place a parchment round on the bottom of the pan and spray again.

Step 2

In a large microwave-safe bowl, heat the chocolate chips and butter in 30-second increments, stirring between each, until just barely melted. Stir until smooth. Whisk in the sugar, espresso powder, salt, and vanilla. Let cool.

Step 3

Add in the eggs and yolk all at once, vigorously whisking until smooth. Whisk in the cocoa powder until just combined. Batter will be thick.

Step 4

In a small but deep bowl or measuring cup, use an electric mixer or immersion blender fitted with a whisk attachment to beat the heavy cream to medium peaks. Using a rubber spatula, gently fold the whipped cream into the batter until combined.

Step 5

Pour the batter into the prepared pan and smooth the top.

Step 6

Bake the cake for about 25 to 30 minutes, or until the cake has puffed up, the edges are set but the center is still slightly wobbly, and the center is at least 200°F using an instant-read thermometer.

Step 7

Remove from the oven and let cool in the pan on a wire rack for 10 minutes. The cake will deflate slightly as it cools. Loosen the edges of the still-warm cake from the pan with a thin flexible knife or offset spatula so it unmolds easier when ready to serve. Let cool completely in the pan. Once cool, cover and refrigerate for at least 6 hours but preferably overnight. At this point, the cake can be kept covered in the fridge for up to 3 days as well as any leftovers.

Step 8

This cake is best served chilled. When ready to serve, remove the cake to a serving plate. Use a sharp knife to cut into slices, running the knife under hot water and wiping off the blade between slices. Place a spoonful of powdered sugar in a small fine mesh strainer and dust over each slice. Top with whipped cream or a scoop of ice cream and a few berries. Serve.