Preheat oven to 350°F (175°C) and line baking trays with parchment paper.
Whisk flour, baking soda, baking powder, and salt in a bowl.
In another bowl, beat butter, peanut butter, and sugars until creamy.
Mix in eggs and vanilla until smooth.
Gradually combine dry ingredients into wet mixture until dough forms.
Add milk if dough feels too stiff.
Scoop large dough balls, roll in sugar, and place on tray.
Flatten slightly with a fork to create the classic crisscross pattern.
Bake 10–12 minutes until edges are set and centers stay soft.
Cool on tray for 5 minutes, then transfer to rack to cool completely.
