Preheat oven to 350℉
Grease a 9-inch tart pan and line with parchment paper
Place blanched almonds in a food processor and pulse until an almond meal forms
Melt butter in a saucepan then remove from heat to cool
Finely chop chocolate with a large knife
Place egg yolks, sugar and vanilla in a bowl and beat until it becomes thick and a pale yellow
Fold the almond meal, chocolate and butter into the mixture above
In a different bowl, beat the egg whites until stiff peaks form. Fold into the chocolate mixture
Spoon mixture into the prepared pan and bake for 50-60 minutes until the cake is just firm to the touch
Cool the cake. Remove from pan and place on a plate. Dust with the powdered sugar and cocoa powder
Serve with vanilla bean ice cream, if desired