To prepare a chocolate peanut butter whoopies baked goods recipe, first you need to prepare the ingredients for the recipe. First, you'll need the following ingredients: 1 cup granulated sugar 1 tablespoon melted butter 1 teaspoon vanilla 2 tablespoons chocolate chips (optional) 2 cups rolled oats 12 cup flour 2 teaspoons baking powder 1/2 teaspoon salt 1/2 cup buttermilk Instructions Preheat the oven to 375 degrees F. Line two 9x9-inch baking pans with foil or parchment paper. Pour the wet ingredients into the dry ingredients and stir to combine. Set aside. In the bowl of an electric mixer, cream the butter and sugar on medium speed until light and fluffy, about 2 minutes. Add the egg and vanilla and beat until combined. Gradually add the flour mixture, beating after each addition until the mixture is just combined and no dry streaks remain. Scrape down the sides of the mixing bowl with the back of your wooden spoon to incorporate any clumps of flour. Sift the cocoa powder, baking soda, cinnamon, and salt. Beat the batter until it's smooth and spreadable. Fill each prepared pan about 34 full with batter. Bake for 20 to 25 minutes or until toothpick inserted in the center comes out clean. Let the cakes cool for 10 minutes before removing to wire racks to cool completely.