This French Onion Soup Casserole turns the classic bistro favorite into a rich, comforting baked dish that’s easy to serve and impossible to resist. Sweet onions are slowly caramelized until golden and fragrant, then simmered in a savory blend of broth and white wine to create that signature deep flavor. The mixture is layered with toasted French bread and generous amounts of Gruyère and Parmesan, building a casserole that captures everything people love about French onion soup — just in a heartier, spoonable form.
Once baked, the cheese melts into a bubbling, golden crust while the bread soaks up the savory onion broth underneath. The result is warm, cheesy, and deeply satisfying with every bite. Perfect for cozy dinners, holiday gatherings, or when you want comfort food with a touch of elegance, this casserole delivers all the soul of French onion soup without the fuss of individual bowls.
