Preheat oven to 350°F. Line two cookie sheets with parchment paper. Whisk flour, baking powder, baking soda, and salt in a medium bowl.
In a large bowl, whisk sugar, melted butter, egg, egg yolk, and vanilla. Stir in the flour mixture until smooth. Fold in oats, pecans, coconut, and chocolate chips.
Lightly spray a ¼-cup measuring cup with oil. Scoop dough onto cookie sheets, spacing 8 portions per sheet, about 2½ inches apart.
Bake for 15–17 minutes, rotating halfway through, until edges are browned and centers are puffed. Do not overbake.
Cool on the sheet for 5 minutes, then transfer to a wire rack. Store in an airtight container for up to 3 days.