Preheat oven to 350°F
Cream butter and sugars until smooth.
Mix in the flour and baking powder.
Then mix in peanut butter, egg ,and vanilla.
Add the flour mixture and mix until combined.
Roll dough into balls and place on a baking sheet.
Flatten with a fork in a criss-cross pattern.
Bake for 9-11 minutes.
Let cookies cool completely on the baking sheet, then enjoy!