In a bowl, combine the flour, sugar, cocoa, baking soda and salt; mix well.
Combine the buttermilk, butter, eggs and vanilla. Add to the dry ingredients; mix well. Fill paper-lined muffin cups 2/3 full. Press a chocolate kiss into the center of each cupcake until batter completely covers candy. Bake at 375 for 20-25 minutes or until a toothpick inserted into the cakes comes out clean.
Cool for 10 minutes before removing from pans to wire rack to cool completely. Frost cupcakes.
For Peanut Butter Frosting, beat cocoa into peanut butter. Gradually add powdered sugar and milk. Add vanilla and additional milk if needed.