This French Onion Beef Stew takes everything comforting about a classic beef stew and layers in the sweet, savory depth of caramelized onions. Tender, fall-apart beef chuck simmers in a rich broth with deeply caramelized onions, then each bowl is topped with toasted bread and melted Gruyère cheese. It's the perfect one-pot dinner for chilly afternoons, and the flavor only gets better the next day.
Pat beef dry, season with 1 teaspoon salt and 1/2 teaspoon pepper. Sear in batches in hot oil until browned on all sides, then transfer to a plate.
Reduce heat to medium, add butter and remaining oil. Cook onions with sugar and remaining salt for 35-40 minutes, stirring frequently, until deep caramel brown.
Add garlic and cook 1 minute until fragrant. Stir in flour and cook 1-2 minutes. Pour in sherry, scraping up browned bits, and simmer until slightly reduced.
Return beef and juices to pot. Add broth, Worcestershire sauce, thyme, and bay leaves. Bring to boil, reduce to low, cover, and simmer 2 hours.
Stir in mushrooms, cover, and cook 20-30 minutes more until beef is fork-tender. Remove thyme and bay leaves, and adjust seasoning.
Preheat broiler. Toast baguette slices 1-2 minutes per side. Ladle stew into broiler-safe bowls, top with toasted bread and shredded Gruyère. Broil 2-3 minutes until cheese is melted and bubbly. Garnish with parsley and thyme.
Notes
Don't rush the onion caramelization - this step creates the deep, sweet flavor that defines the stew. Slice onions evenly so they cook at the same rate.
Pat the beef completely dry before searing to ensure a good brown crust instead of steaming.
Work in batches when searing the beef to avoid overcrowding the pot.
This stew tastes even better the next day once the flavors have had time to meld together.
To freeze, cool completely and store in freezer-safe containers without the bread topping for up to 3 months.
Substitute dry red wine for the sherry for a more traditional braise flavor.
Use Swiss cheese instead of Gruyère for a milder, more budget-friendly option.
For a slow cooker version, caramelize onions and sear beef on stovetop, then transfer to slow cooker on low for 7-8 hours.
Add cubed carrots and potatoes along with the mushrooms for a more traditional stew texture.
Reheat gently on the stovetop over medium-low heat, adding fresh toasted bread and cheese only when ready to serve.