To make sponge cake: Place the eggs and sugar into a bowl standing over hot water and whisk until the mixture is pale and thickened (about 5 minutes). Remove from the heat and whisk for 2 minutes more. Fold in the sifted flour and add the salt. Pour into an 8-inch cake tin which has been greased, sugared and floured. Bake in a 375 degree oven for 25 minutes. Cool on a cake rack.
To make pastry cream: Heat milk until boiling. Mix the egg yolks with the sugar and when well combined add the flour. Whisk until smooth and then gradually add the hot milk. Place the pastry cream back into the saucepan over a gentle heat and whisk until cream comes to a boil and thickens. Flavor with almond extract and then lower heat and allow to cook 10 minutes. Remove from heat and cool placing a piece of buttered waxed paper over the surface to prevent a skin from forming.
To make meringue: Beat the egg whites until stiff peaks form. Flavor with almond extract and then fold in the sugar. This mixture should be very thick.
To garnish: Preheat oven to 500 degrees. Cut cake into 3 layers. Soak bottom and middle layer with creme de cacao. Spread the bottom and middle layers of the cake with the cooled pastry cream and sprinkle with the almond slivers. Reform the cake and place onto a large round oven dish. Spread cake with a thin layer of meringue. Fill a large piping bag with a rose shaped tip and pipe meringue in vertical loops around the sides and on top of the cake. Dust cake with sifted confectioners' sugar and place into oven for 3 minutes to lightly brown.