Preheat oven to 350°F. Grease a 9 x 9 pan.

In a medium bowl cream together the peanut butter and butter.

Gradully blend in the white sugar, brown sugar, egg, and vanilla, Mix untill light and fluffy.

In a seperate bowl, combine the flour, baking powder, and salt. Stir into the peanut butter mix. Fold in chocolate chips until they are spread throughout.

Spread into pan and bake 25 -35 minutes.

Remove from oven and sprinkle with remaining chocolate chips.

Allow to cool completely before cutting into squares.