Miniature panna cotta tarts with Greek-yogurt put a spin on a classic dessert and are the perfect sweet treat to serve to wedding guests.
Lightly beat together yolks and the cold water in a small bowl or glass measure until combined.
Pulse flour, sugar, and salt in a food processor until combined. Add butter, and pulse until mixture resembles coarse crumbs with some larger pieces remaining, about 10 seconds. Drizzle in yolk mixture, and pulse until dough just begins to hold together (no longer than 30 seconds).
Divide dough in half, shape into disks, and wrap in plastic. Refrigerate until firm, 30 minutes or overnight.
Roll out one dough piece to 1/4-inch thickness on a lightly floured surface. Cut into twelve 4-inch circles. Fit dough into 3-inch fluted tart shells. Repeat with remaining dough. Place pans on a rimmed baking sheet, and freeze for 30 minutes.
Preheat oven to 375 degrees. Prick bottoms of shells with a fork. Line shells with parchment paper or cupcake liners; fill with baking beans. Bake for 5 minutes; reduce heat to 350 degrees, and bake for 30 minutes more. Remove beans and liners; bake for another 10 minutesor until completely baked through and golden brown. Transfer to a rack to cool. Tart shells can be stored in an airtight container up to 2 days.
Pour panna cotta into fully cooled prepared tart shells. Refrigerate for 2 hours until set. Before serving, garnish with candied grapefruit peel.