Heat oven to 350°F. Line two baking sheets with parchment.
Whisk flour, baking soda, baking powder, and salt in a bowl.
Cream butter, peanut butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the egg and vanilla until smooth.
Mix in the dry ingredients just until combined. Add the milk only if the dough feels dry.
Scoop dough into 1-tablespoon portions and roll into balls.
Roll each ball in granulated sugar, then coat generously in powdered sugar.
Arrange on prepared sheets, spacing about 2 inches apart.
Bake 9–11 minutes, until tops crack and edges look set but centers are soft.
Cool on the sheet 5 minutes, then move to a rack to finish cooling.
Notes
For a spiced twist, mix 1/2 tsp cinnamon into the powdered sugar, or swap in crunchy peanut butter for extra texture. Store cookies airtight at room temperature up to 4 days. Freeze unbaked, sugar-coated dough balls up to 2 months; bake from frozen, adding 1–2 minutes.This recipe is an original creation inspired by classic Easy Holiday Peanut Butter Crinkles flavors. All ingredient ratios and instructions are independently developed.