Created by parsley101 on March 1, 2014
Step 1: Heat oven to 350°F. Grease bottom and sides of 1 (13x9-inch) pan or 2 (9-inch) round cake pans with shortening; lightly flour.
Step 2: For the cake; in small bowl combine flour with next 3 dry ingredients.
Step 3: In a large bowl cream butter. Add in sugar then eggs bowl, beat or 2 minutes scraping bowl constantly. Add buttermilk, beat until combined. Using a spatula mix in the mashed banana. On low speed mix in flour mixture until just combined. Mix in walnuts. Pour into pan(s).
Step 4: Bake 13x9-inch pan 45 to 50 minutes, round cake pans 35 to 40 minutes, or until toothpick inserted in center comes out clean. Cool round cakes 10 minutes before removing from pans to cooling racks. Cool completely, about 1 hour.
Step 5: For the frosting; in medium bowl, beat peanut butter and powdered sugar with spoon or electric mixer on low speed until blended. Add vanilla and 1/4 cup milk; beat until smooth and spreadable. If necessary, beat in more milk, a few drops at a time. Frost 13x9-inch cake, or fill and frost round cake layers with frosting.
Step 6: Sprinkle salted chopped peanuts over the top.