Marbled Citrus Tart

Name: Marbled Citrus Tart
Prep time: 30 min
Cook time: 5 h
Total time: 5 h 30 min
Cuisine: European, Mediterranean, French
Ingredients: 3/4 cup unsalted butter, cubed and cold; 1/3 cup powdered sugar; 1 1/2 cups all-purpose flour; 1 lime, zested; 1 pinch salt; 1/2 cup blood orange juice plus zest (optional); 1/4 cup granulated sugar; 1 tablespoon cornstarch; 2 large eggs; 3 tablespoons unsalted butter, cubed; 1/2 cup meyer lemon juice plus zest (optional); 1/2 cup grapefruit juice plus zest (optional)