Beat softened butter, granulated sugar, and brown sugar for 2–3 minutes until fluffy.
Mix in the egg and vanilla until smooth.
Whisk flour, baking soda, baking powder, and salt in a separate bowl.
Gradually mix dry ingredients into the wet until a soft dough forms.
Cover and chill dough for 30 minutes.
Preheat oven to 350°F (175°C). Scoop 2 Tbsp dough per cookie onto a lined baking sheet. Press a dill pickle slice into each.
Bake 10–12 minutes until edges are golden. Cool 5 minutes on the sheet, then transfer to a rack.