Grease a 9-inch (23-cm) petal-patterned cake pan.
Preheat oven to 375°F(190°C).
To make cake, mix almonds, half the sugar, vanilla, salt, whole egg and 6 egg yolks in a large bowl.
Beat until creamy.
Beat egg whites until stiff; fold in remaining sugar.
Fold egg white mixture into egg yolk mixture.
Sift flour and baking powder over mixture and fold in carefully.
Fold in chocolate pieces.
Turn batter into greased cake pan; smooth the surface.
Bake 45 to 50 minutes or until a wooden pick inserted in center comes out clean.
Cool cake slightly in cake pan then transfer to a rack to cool completely.
To make frosting, melt chocolate in a double boiler over low heat.
Spread over top and sides of cooled cake.
Sprinkle with pistachios while chocolate is soft.