Preheat oven to 375° F. Line rimmed baking sheets with parchment paper or silicon baking mat.
Cream together butter, peanut butter, sugars, vanilla, milk, and egg.
Whisk together all dry ingredients and cream with peanut butter mixture until just combined. Be careful to not over mix.
Scoop 1 tablespoon of dough and roll into a ball and then roll in sugar and place on baking sheet about 2 inches apart as the cookies will spread.
Place in preheated oven and bake between 10 – 15 minutes, depending on your oven.