Mix the butter, peanut butter, sugar, brown sugar and egg together.
In a separate bowl, mix together your remaining dry ingredients.
Add your dry ingredients to your wet ingredients and mix.
Shape dough into 2-inch balls and place them 3 inches apart on the cookie sheet. Dip a fork in sugar and press in a crisscross pattern on each ball to flatten to about 2 inches.
Bake 8 minutes or until golden browmn. Immediately remove the cookies to a cooling rack.