Caramelize Onions

1. In a large skillet, toss sliced onions with butter and olive oil, then cook on medium heat, stirring often.
2. After about 10 minutes, the onions will start to soften; continue cooking for a total of 25 to 35 minutes until golden.
3. If they stick, add a splash of water and scrape up the browned bits.

Slow Cooker Preparation

1. Transfer caramelized onions to the slow cooker.
2. Add minced garlic and stir in.
3. If using flour, sprinkle it over the onions and stir for a minute to coat.
4. Add wine if using, then pour in the beef broth.
5. Stir in Worcestershire sauce, thyme, pepper, salt, and bay leaf.
6. Cook on LOW for 7 to 8 hours or HIGH for 3 to 4 hours.
7. Before serving, taste and adjust salt, and remove the bay leaf.

Prepare Cheesy Toast

1. Slice baguette into thick pieces and toast until crisp.
2. Top toasted bread with a generous pile of shredded Gruyère.
3. Optionally, rub the toast with a cut garlic clove before adding cheese.

Serve

1. Ladle soup into oven-safe bowls, set cheesy toast on top, and broil until bubbling and lightly browned.
2. If you don’t have oven-safe bowls, toast the cheesy toasts on a baking sheet and place one on each bowl of soup before serving.