Heat oven to 350° F.
Line a standard 12-cup muffin tin with paper liners. In a medium bowl, whisk the flour, baking powder, and salt. In a large bowl, whisk the butter and sugars until smooth. Whisk in the egg and vanilla. Gradually stir in the flour mixture, then stir in the chocolate chips.
Divide the batter evenly among the prepared muffin cups. Bake until the centers are just set and a toothpick inserted comes out with moist crumbs, 25 to 30 minutes.