Cream butter & sugar; beat until light & fluffy. Add eggs one at a time, beating well after each addition. Blend in peanut butter, then flour. Pour into 2 lightly greased 9x5 inch loaf pans. Bake in a pre-heated 350 degree oven for 50-60 minutes or until centers test done. After about 15 minutes of baking, sprinkle finely chopped peanuts onto the batter to give a crunchy topping.