Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
Whisk together the flour, baking powder, and salt in a bowl. Set aside.
Beat the softened butter and granulated sugar together until light and fluffy, about 2-3 minutes.
Add the egg and vanilla extract. Mix until just combined.
Stir in the flour mixture gradually until a soft dough forms. Do not overmix.
Roll dough into 1.5-inch balls, place 2 inches apart on prepared sheets, and flatten slightly with your palm.
Melt 2 tbsp butter with brown sugar in a small saucepan over medium heat. Stir until glossy, about 2 minutes.
Cut pineapple into small pieces that fit each cookie. Press one piece onto each dough round.
Spoon a small amount of brown sugar butter over each pineapple piece, then press a cherry half in the center.
Bake for 12-14 minutes until edges are set and bottoms are lightly golden. Cool on the pan for 5 minutes before transferring.