Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone mat.
Beat butter and sugar until light and fluffy, then mix in egg yolk, vanilla, and coconut extract until smooth.
Stir in flour and salt just until combined, then fold in shredded coconut. If the dough feels sticky, chill for 10 minutes.
Scoop 1-inch dough balls and place 2 inches apart on the sheet. Press a small indentation in each and fill with about ½ teaspoon lemon curd.
Bake 10–12 minutes, until edges turn lightly golden. Cool 5 minutes on the pan, then move to a rack to cool completely.
Dust with powdered sugar and sprinkle with toasted coconut flakes before serving.