Preheat oven to 325 F.
Melt chocolate, butter, vanilla and espresso powder in a stainless steel bowl over simmering water. Don’t let the bottom of the bowl touch the water.
Beat egg whites, gradually adding the sugar, until soft peaks. Don’t over beat. Set aside.
Butter a 9-inch spring form pan and dust with almond flour.
Beat the egg yolks and combine with the chocolate mixture. Add the almond flour, salt, and cocoa; combine well, but do not beat. Fold in egg whites. Pour into prepared pan.
Bake 50 minutes. Cool completely. Remove from pan and dust with icing sugar.
