Preheat oven to 375° F. Grease and flour a 9" spring form pan.
Sift together flour, baking powder and salt. Cream the butter until fluffy, add sugar gradually, beating until light. Add eggs one at a time, beating well after each addition. Add vanilla. Add dry ingredients 1/3rd at a time alternating with the 6 tablespoons of milk. Stir only enough to blend thoroughly. Pour into the spring form pan.
The topping: Heat together almonds, sugar, butter and milk or cream until the
sugar dissolves. Pat a spoonful of flour over the top of the cake batter using the back of a spoon. Pour the almond mixture evenly over the batter. Bake 25 minutes or until cake tester comes out clean. Cool cake while preparing filling.
The filling: Combine sugar, cornstarch and egg yolks in the top of a double boiler. Separately heat milk to scalding, slowly pour over egg yolk mixture, stirring constantly and quickly with a whisk. Place over hot water, cook stirring constantly until smooth and thick. DO NOT ALLOW TO BOIL. Stir in almond extract. Beat egg whites, adding the salt, until stiff peaks form. Fold egg whites into the yolk mixture. Place a piece of wax paper over the top and chill.
Putting it all together: When the cake has cooled, slice in half crossways to
make two layers. Place bottom layer cut side up on cake plate. Spread with
filling. Top with the second layer with the almond glazed side up.
Refrigerate until time to serve.