1. Heat oven to 350 degrees F. Coat two 9-inch-round cake pans with nonstick cooking spray. Line bottom with waxed paper circles.
2. Stir together flour, baking powder and salt in medium-size bowl.
3. Beat together butter and sugar in a large bowl until light and fluffy. Beat in eggs until fluffy. Beat in peanut butter and vanilla until well blended.
4. On low speed, alternately beat flour mixture with milk into butter mixture, in three additions. Scrape into prepared pans, dividing equally.
5. Bake in 350 degree F oven for 25 minutes or until wooden pick inserted in centers comes out clean. Cool cakes in pans on racks for 10 minutes. Remove cake from pans to racks to cool completely.Prepare Frosting:
6. On low speed, beat butter, milk, vanilla, coffee, cocoa powder and confectioners sugar in bowl until smooth.
7. For filling, stir together 3/4 cup frosting and chopped peanut butter cups in small bowl.
8. Place cake layer, top side down, on plate. Slip strips of waxed paper under edges of cake. Spread filling over top of cake. Top with second layer, top side down. Spread 1 generous cup frosting over sides, remainder over top. Remove strips. Garnish with curls. Refrigerate; remove 2 hours before serving. Makes 16 servings.Marble Curls:
9. Line baking sheet with foil. Coat lightly with nonstick cooking spray. Melt 1 package (10 ounces) white chocolate chips, according to package directions. Place half of the mixture in small bowl; tint with red food coloring. Alternately spoon pink and white mixtures on baking sheet. Swirl with knife to marbleize. Refrigerate for 30 minutes or until firm. Cut lengthwise in strips equal to width of vegetable peeler. Scrape peeler along strips top to form curls. Refrigerate or freeze until needed.