Preheat oven to 350 F. In a medium bowl, combine butter and sugars. Add eggs and vanilla; beat until smooth. In a small bowl, combine flour, cinnamon, baking powder, and salt. Add dry ingredients to butter mixture; stir just until dry ingredients are moistened. Stir in peanut butter. Spread batter into a greased 7 x 11 inch metal baking pan. brownies.