Alsace Onion Tart

Name: Alsace Onion Tart
Ingredients: 2 cups all-purpose flour; 1 stick (1/2 cup) cold unsalted butter, cut into 1/2-inch cubes; 1/4 cup vegetable shortening; 1/2 teaspoon salt; 4 to 5 tablespoons ice water; 4 bacon slices (1/4 lb), cut crosswise into 1/8- to 1/16-inch-wide strips; 3 tablespoons unsalted butter; 2 lb onions, halved lengthwise and very thinly sliced crosswise (10 cups); 1 1/4 teaspoons salt; 1 teaspoon black pepper; 1 cup crème fraîche or heavy cream; 4 large eggs; 1/2 teaspoon freshly grated nutmeg; 1 11-inch tart pan (1 1/4 inches deep) with a removable bottom; N/A pie weights or raw rice; a pastry scraper; an 11-inch tart pan (1 1/4 inches deep) with a removable bottom; pie weights or raw rice