1Preheat oven to 350 degrees. Line standard muffin tins with paper liners. Whisk dry ingredients in a large bowl. Cream butter and sugar with a mixer until light and fluffy. Add eggs, 1 at a time, beating after each addition.
Reduce speed to low. Mix any remaining wet ingredients in a bowl if needed. Add dry ingredients to butter mixture in 3 additions, alternating with wet ingredients and ending with dry. Scrape sides of bowl. Divide batter among muffin cups, filling each 2/3 full.
Bake cupcakes until testers inserted into centers come out clean, about 20 minutes. Let cool in tins on wire racks. Cupcakes will keep, covered, for up to 3 days, unless otherwise noted.
21.Make cupcakes as directed in Basic Cupcake How-To, using mashed bananas, buttermilk, and vanilla for wet ingredients.
Stir pecans into batter. Once cupcakes are cool, frost tops with caramel buttercream. Frosted cupcakes will keep, covered and refrigerated, for up to 2 days. Top with banana slices before serving.