Preheat oven to 400 degrees F.
Roll out pastry and cut into four equal rounds. Using fingers, fit pastry into four tart pans with removable bottoms. Line each with parchment paper and fill with pie weights or dry beans. Bake until crisp (no soggy bottoms!), approximately 30 minutes. Cool completely.
Fill each tart shell with ¼ C grapefruit curd. Sprinkle one tablespoon sugar over each. Using a culinary torch or broiler, brulee each until browned and hard like glass.
Top each with grapefruit sections and serve.