Mix flour, sugar, salt and baking powder together. Cut in the peanut butter and butter, then add eggs and milk. Stir until moistened. Be sure to grease the muffin pan. Makes about 12, but they are large, so you can divide the batter into 16. Bake at 400 degrees for 15-17 minutes.
Dip the top of each muffin into the melted butter, and roll in the cinnamon-sugar mix.
I put about a cup of chocolate chips into mine, and they were heavenly!!!