Step 1: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Step 2: In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well combined.
Step 3: In a large bowl, cream the softened butter and granulated sugar together using an electric mixer until the mixture is light, fluffy, and pale in color.
Step 4: Beat in the egg and vanilla extract to the butter-sugar mixture until fully incorporated.
Step 5: Gradually add the flour mixture to the wet ingredients, mixing gently until just combined to form the dough. Avoid overmixing.
Step 6: Roll the dough into 1-inch (2.5 cm) balls and place them evenly spaced on the prepared baking sheet.
Step 7: Using your thumb or the back of a spoon, make a small indentation in the center of each dough ball to create a thumbprint.
Step 8: Fill each indentation with approximately 1 teaspoon of lemon curd.
Step 9: Sprinkle the top of each cookie with toasted shredded coconut, pressing gently to adhere.
Step 10: Bake the cookies for 12 to 15 minutes, or until the edges are golden brown.
Step 11: Immediately upon removing from the oven, sprinkle extra shredded coconut over the top for added texture and flavor.
Step 12: Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.