Ingredients
- 6 large yellow onions, thinly sliced
- 3 tbsp unsalted butter
- 1 tbsp olive oil
- 1 tsp salt
- 1 tsp sugar (optional, helps caramelization)
- 1/4 cup dry white wine or sherry
- 6 cups beef stock (or a mix of beef and chicken stock for milder flavor)
- 2 sprigs fresh thyme (or 1/2 tsp dried thyme)
- 1 bay leaf
- Salt and pepper to taste
- 1 baguette, sliced and toasted
- 1 1/2 cups shredded Gruyère cheese (or Swiss cheese)
Instructions
1. Prepare Onions
- Peel and thinly slice onions. (Tip: Use a mandoline for faster, consistent slicing.)
2. Quick Caramelization Hack
- Heat butter and olive oil in a large pot or Dutch oven over medium heat.
- Add onions, salt, and sugar (if using). Stir to coat.
- Cover the pot with a lid and cook for 10 minutes on medium-low, stirring occasionally. This helps onions soften and steam without drying out.
- Remove the lid, increase heat to medium, and stir every few minutes. Keep an eye on them so they brown evenly but don’t burn. After 30 minutes total cooking time, they’ll be golden and caramelized. (Shortcut: Adding 1-2 tbsp of water as needed can deglaze the pan and speed up caramelization.)
3. Deglaze the Pot
- Stir in white wine or sherry, scraping up any browned bits from the bottom. Let simmer for 2 minutes to cook off the alcohol.
4. Add Broth and Seasonings
- Pour in beef stock. Add thyme and bay leaf. Bring to a boil, then reduce to a simmer. Cook uncovered for 20-30 minutes to let the flavors meld.
- Remove thyme sprigs and bay leaf. Taste and adjust salt and pepper.
5. Assemble and Serve
- Preheat your broiler. Ladle soup into oven-safe bowls.
- Top each bowl with a slice of toasted baguette and a generous handful of Gruyère cheese.
- Broil until cheese is melted and bubbly, about 2-3 minutes. Keep a close eye to avoid burning.
6. Serve Hot
- Enjoy with extra bread on the side and a glass of white wine (because you deserve it)!
Time Saving Tip
- If you’re really in a rush, caramelize onions in a slow cooker overnight with butter and a touch of salt, then use them in the soup.
- Gruyère is the classic cheese, but feel free to mix in mozzarella or parmesan for extra gooeyness.