- 7 tablespoons unsalted butter, divided
- 1 tablespoon olive oil
- 3 pounds thinly sliced yellow onions
- 4 thyme sprigs
- 1 teaspoon sugar
- 1/2 teaspoon salt
- 1 tablespoon all-purpose flour
- 1 cup white wine
- 8 cups low-sodium beef broth
- 1 baguette
- 1 pound shredded Gruyère cheese
- calories 530
- fat 31 g
- satfat 17 g
- protein 25 g
- carbohydrate 36 g
- fiber 3 g
- cholesterol 89 mg
- sodium 949 mg
How to Make It
Melt 4 Tbsp. unsalted butter and 1 Tbsp. olive oil in a large pot. Add 3 lb. thinly sliced yellow onions and 4 thyme sprigs; cook, covered, on medium-low heat for 20 minutes, stirring often.
Uncover, add 1 tsp. sugar and 1/2 tsp. salt. Cook, stirring often, until onions are deep brown and caramelized, 30 to 40 minutes. Add 1 Tbsp. all-purpose flour; cook for 2 minutes more, stirring.
Add 1 cup white wine and 8 cups low-sodium beef broth; stir up browned bits on bottom of pot. Lower heat and simmer for 30 minutes; stir occasionally. Season with pepper.
Preheat oven to 425ºF. Cut 1 baguette into 8 thick slices. Spread both sides with 3 Tbsp. unsalted butter; place on a baking sheet. Toast until golden on both sides, 5 to 8 minutes, turning over once.
Fill 8 bowls with soup. Place a slice of toast on top of each bowl. Divide 1 lb. shredded Gruyère on top. Set bowls on baking sheets; bake until cheese is bubbly, 5 to 10 minutes.