Intensely fudgy and chocolatey with a slight almond crunch, no one can resist this simple, decadent and beautiful cake!
Preheat oven to 350°F/180°C. Grease the bottom and sides of an 8-inch/20cm (or a 9-inch/23 cm) springform pan. Wrap the outside bottom and sides of the pan with aluminum foil to prevent leaking.
In a mixer bowl fitted with a whisk attachment, whisk egg whites and the remaining ½ cup of sugar on high speed until thick, shiny, soft peaks form.
Pour batter into prepared cake pan and smooth the top. Bake for 35-45 minutes, until a toothpick inserted into the center comes out with moist crumbs. The cake should be set on the sides but still wobbly in the center. Allow to cool on a wire rack, then refrigerate for at least 4 hours until completely set.
Sift cocoa powder over cake before serving. Serve chilled or at room temperature.
Cake will keep, well wrapped, in the refrigerator for up to 4 days. It also freezes well.