Frankfurt Crown Cake

Prepare the cake: Cream the butter and 1 1/2 cups sugar until very light and fluffy, about 5 minutes. Beat in the egg yolks, one at a time. Mix in the lemon rind and 2 tablespoons rum. Sift the baking powder and flour together. Gently mix into the butter mixture. Beat the egg whites until stiff but not dry. Gently fold the egg whites into the batter. Pour into a well-greased 10-inch tube pan. Bake in a preheated 325°F oven for about 60 minutes or until the cake tests done. Cool cake in pan for 10 minutes, then turn out on wire rack to cool completely. Slice cake crosswise into 3 layers. Pour about 2 tablespoons of rum over each layer.

Prepare the butter-cream filling: Boil 1 cup sugar and 3/4 cup water to 238°F (114°C), soft ball stage. Beat 6 egg yolks until very light and fluffy, 5 to 10 minutes. While still beating the egg yolks, add the sugar syrup in a thin stream. Beat 5 minutes more, until very thick and doubled in bulk. Slowly beat in 1 tablespoon rum. Beat 1 cup butter in a small bowl until soft and light. Beat butter into the egg mixture a little at a time. Continue beating until thick. Chill until mixture can be spread. If mixture is too soft, beat in additional butter.

Prepare the praline topping: Spread 2 tablespoons butter thickly in a 9x13-inch baking pan. In a 1-quart saucepan, boil 1 cup sugar and 1/2 cup water to 238°F (114°C), soft ball stage. Stir in 1 cup blanched, sliced almonds; cook until mixture reaches 310°F (154°C) or until syrup caramelizes. Pour syrup into prepared baking pan. When cool, break up praline and grind it in a blender for a few seconds.

Prepare the apricot glaze: Heat 1/2 cup apricot jam and press through a strainer or sieve to make apricot glaze.

Assemble the cake: Place bottom layer of cake on cake plate and spread with half of the buttercream. Repeat with second layer. Place third layer on top. Spread top and sides of cake with apricot glaze. Press praline powder onto glaze. Any remaining buttercream can be used to decorate the top of the cake.