If you're looking for a tart that truly embodies richness and luxury, this Alsace Onion Tart, also known as a French Onion Tart, is for you. With a golden, buttery crust and a creamy filling bursting with tender onions, smoky bacon, and aromatic thyme, this dish is pure comfort. Topped with a generous sprinkle of grated Gruyère cheese, this is an indulgent dish. Serve it as a main meal for lunch, dinner, or brunch, or slice it into smaller portions and serve it as an appetizer.