Drain crushed pineapple through a fine mesh strainer, pressing firmly for 2 minutes. Blot dry if needed.
Preheat oven to 350°F. Line a sheet pan with parchment.
Cream butter and sugar until lightened.
Mix in egg and vanilla until smooth.
Stir in drained pineapple.
Add flour, baking powder, and salt. Stir until just combined.
Scoop into 1 1/2-tablespoon portions, spaced 2 inches apart.
Bake 10–12 minutes until edges are golden. Cool on pan 5 minutes before transferring.
For best results, drain the pineapple thoroughly to avoid soggy dough. These pineapple cookies are a fun twist for baby showers or tropical events.