Preheat the oven to 375 degrees. Line the bottom of 1 of each size of the pans with parchment paper. Sift the flour with the salt. In a mixer fitted with a whip attachment, beat the egg yolks with 8 ounces of sugar until light and fluffy and tripled in volume. Beat the egg whites with the remaining 7 ounces of the sugar until soft peaks form. Fold the egg yolks gently into the egg whites. Gently fold in the sifted flour. Gently fold in the melted butter and the vanilla. Pour the batter into each of the 3 pans. Bake for 20 to 25 minutes, or until center is set. Remove from the oven and run a knife around the edge of the pan to loosen it and cool on wire racks. Repeat this procedure to make 1 more layer of each size.

In a saucepan, combine sugar and water. Heat to a temperature of 248 degrees F on a candy thermometer. In an electric mixer on medium speed, beat the egg whites with the salt until they hold stiff peaks. With the mixer running, drizzle the hot syrup into the whites being careful not to hit the whip with the hot syrup. Beat mixture at medium speed until cooled to room temperature, 15 to 20 minutes. Turn the mixer down to low and add the softened butter, piece by piece. **It is very important that the butter and the meringue are the same temperature. If the buttercream begins to break, Slowly heat it up to about 95 degrees F. over a double boiler, while whisking. Return to the mixer and beat until it comes back together. Continue adding butter*** Mix in the vanilla.

To assemble: Cut each of the cooled cakes in half horizontally. Stack each of 4 layers of each size, icing in between each layer on a corresponding size cake circle. Make 3 separate 4-layer cakes. Ice each of the cakes separately. Place the 12 by 2-inch cake on a large platter. Cut 3 lengths of the wooden dowel that are as long as the 12-inch cake is high. Insert the dowels in a triangle pattern in the center of the 12-inch cake. Cut 3 more dowels that are as long as the 9-inch cake is high. Carefully place the 9-inch cake on top of the 12-inch cake in the center, on top of the dowels. Insert the dowels into the center of the 9-inch layer in a triangle pattern. Carefully place the 6-inch layer on top of the 9-inch layer. Decorate with fruit, flowers and marzipan