Grease a 15x10x1-inch baking pan. Line with waxed paper. Grease and flour waxed paper; set aside. Beat egg whites, salt, and cream of tartar in a large bowl with an electric mixer on high speed until stiff peaks form (tips stand straight).

Beat egg yolks in a medium bowl with an electric mixer on high speed for 5 minutes or until thick and pale. Gradually add granulated sugar, beating on high speed until sugar is almost dissolved. Stir in the 1 teaspoon vanilla and the ground almonds. Stir flour, nutmeg, and cinnamon together; gently stir into egg yolk mixture. Fold about one-fourth of the egg white mixture into the flour mixture to lighten. Fold remaining egg white mixture into flour mixture just until combined. Spread in the prepared pan. Bake in a 350 degree F oven for 12 to 15 minutes or until cake springs back. Do not allow to brown.

Immediately loosen cake from pan. Invert cake onto a towel sprinkled with powdered sugar. Remove waxed paper. Roll up warm cake and towel together, jelly-roll style, starting from a short side. Cool completely on a wire rack.

For almond filling, beat the 1-3/4 cups whipping cream in a large bowl with an electric mixer on medium speed until soft peaks form (tips curl over); set aside. Finely crumble almond paste into a medium bowl. Add the 1/4 cup whipping cream and the amaretto or 2 teaspoons vanilla. Beat with an electric mixer on low speed until nearly smooth. Fold about one-fourth of whipped cream into almost paste mixture to lighten. Fold remaining whipped cream into almond paste mixture.

Gently unroll cake. Spread half of the almond filling on cake to within 1 inch of the edges. Roll up cake, without towel, into a spiral, starting from a short side. Place on a serving plate. Lightly frost cake with remaining filling and sprinkle with toasted sliced almonds. Garnish with purchased marzipan pigs for luck or assorted fruits, if desired. Makes 12 servings.

Refrigerate prepared cake, covered, for up to 8 hours.