Low-Carb French Onion Soup
Classic French onion soup without the bread: 2 1/2 pounds of onions caramelized slowly in butter, simmered in beef broth with garlic, thyme, bay leaves and Worcestershire, then broiled under a browned Gruyere crust. 12g net carbs a one-cup serving.
Equipment
- Dutch oven or heavy soup pot
- Wooden spoon for scraping the pot
- Oven-safe soup bowls
- Baking sheet
Ingredients
For the soup
- 2 1/2 lb yellow onions about 5 medium, halved and thinly sliced
- 2 tbsp unsalted butter
- 5 3/4 cups beef broth bone broth or regular; divided
- 4 cloves garlic minced
- 1 tbsp fresh thyme leaves stripped from the stems
- 1 tbsp Worcestershire sauce
- 2 bay leaves removed before serving
- 1/2 tsp salt plus more to taste
- 1/4 tsp black pepper freshly ground
For the topping
- 8 oz Gruyere cheese freshly shredded
Instructions
Make the soup
- Caramelize: Heat the butter and 2 tbsp of the broth in a Dutch oven over medium heat. Add the onions and salt and cook about 40 minutes, stirring every few minutes and adding another 2 tbsp of broth after 20 minutes, until deep amber brown and jammy. Lower the heat if the bottom darkens too fast.
- Aromatics: Push the onions aside, add the garlic and thyme to the center and cook 1-2 minutes until fragrant, then stir together.
- Deglaze: Add 1/4 cup of the broth and the Worcestershire sauce and scrape up the browned bits. Add the remaining broth, the bay leaves and the pepper and bring to a boil.
- Simmer: Cover, reduce the heat and simmer 30 minutes. Remove the bay leaves and season with salt to taste.
Broil the topping
- Broil: Ladle the soup into oven-safe bowls on a baking sheet, top each with about 1 oz of the Gruyere cheese and broil 2-4 minutes, until melted, bubbling and browned in spots. Serve carefully; the bowls are very hot.
Notes
Do not rush the onions: they need about 40 minutes over medium to medium-low heat to turn deep brown. Pale onions make a sweet, thin soup.
Lower carb: a 3/4-cup serving has 9g net carbs.
Nutrition is for 1 of 8 servings (about 1 cup) with 1 oz of Gruyere; the bay leaves are not counted.
Storage: keep the soup without the cheese up to 4 days in the fridge or 3 months in the freezer. Reheat, then add the cheese and broil.