These tiny tart shells filled with tangy lemon curd are topped with a sugar-dusted blueberry.
Pulse flour and sugar in a food processor to combine. Add butter; pulse until mixture resembles coarse meal. In a small bowl, lightly beat egg yolk and ice water. With the motor running, slowly pour egg mixture into processor; mix until dough just comes together. Place on plastic wrap; press to flatten into a disk. Wrap; chill at least 1 hour.
Preheat oven to 350 degrees. On a clean work surface, roll out dough 1/8 inch thick. Using a 3 1/2-inch biscuit cutter, cut out 15 rounds. Fit rounds into pans; press into bottom and sides. Chill 30 minutes.
Line tarts with parchment; fill with pie weights or dried beans. Bake 15 minutes; remove paper and weights. Continue baking until golden, about 10 minutes. Transfer to wire rack to cool completely.
Using a toothpick, dip each blueberry in the meringue-powder mixture; roll in sugar. Transfer to a parchment-lined baking sheet; let dry 30 minutes.
Remove tart shells from pans. Fill each shell with about 2 teaspoons lemon curd, and top with a sugared blueberry. Serve chilled or at room temperature.
We baked these treats in mini brioche pans; small fluted tartlet pans would work just as well.