Grease and flour two 9x1 1/2-inch layer cake pans. Sift together flour, baking powder and salt onto wax paper. Beat together butter, sugar and peanut butter in a large bowl with mixer at high speed until well blended. Gradually beat in eggs. Beat in flour mixture alternately with milk until well blended. Add vanilla.

Pour into prepared pans, equally dividing batter. Bake in preheated oven (350 degrees) for 30-35 minutes or until tests done. Cool in pans for 10 minutes, then invert onto cake racks. Cool completely. Spread jelly between layers. Frost top and sides with Peanut Butter Frosting:

Beat together 2 1/2 tablespoons softened butter and 2 tablespoons peanut butter in small bowl until light and fluffy. Stir in 1 1/4 teaspoons vanilla. Beat in 2 cups sifted 10X (confectioners) sugar alternately with 3-4 tablespoons milk until of a good spreading consistency. Garnish top with stripes or circles or webs of jelly.