Ingredients (Serves 4)
For the soup:
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4 large yellow onions, thinly sliced
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3 tbsp unsalted butter or ghee
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1 tbsp olive oil
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2 cloves garlic, minced
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1 tsp fresh thyme (or 1/2 tsp dried thyme)
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1/2 tsp salt (adjust to taste)
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1/4 tsp black pepper
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1/4 tsp xanthan gum (optional, for thickening)
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1/2 cup dry white wine or dry sherry (optional, adds depth)
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4 cups beef broth (or chicken/vegetable broth for lighter flavor)
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1–2 tsp Worcestershire sauce (low-sugar) or soy sauce
For the topping:
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1 cup shredded Gruyère or Swiss cheese (or a mix with mozzarella)
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Optional: 2 tbsp grated Parmesan for extra flavor
Instructions
1. Caramelize the onions
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Heat butter and olive oil in a large pot over medium-low heat.
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Add sliced onions and a pinch of salt. Cook slowly, stirring frequently, until deep golden brown and sweetly caramelized—about 30–40 minutes.
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Add garlic and thyme in the last 2 minutes of cooking.
2. Deglaze and simmer
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Increase heat to medium and add wine or sherry. Scrape the browned bits from the bottom of the pan.
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Stir in broth and Worcestershire sauce.
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Bring to a gentle simmer and cook for 15–20 minutes.
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Optional: sprinkle xanthan gum to thicken slightly, stirring until smooth.
3. Prepare the cheese topping
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Preheat the oven broiler.
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Pour soup into oven-safe bowls.
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Sprinkle shredded cheese generously on top.
4. Broil
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Place bowls on a baking sheet and broil until cheese is bubbly and golden brown (2–5 minutes, watch closely!).
5. Serve
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Carefully remove from oven (hot!). Serve immediately.
Keto Tips:
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Skip the bread traditionally used in French onion soup and let the cheese do the work of a crusty topping.
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Use low-carb beef broth to keep carbs minimal.
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For extra creaminess, swirl in 2–3 tbsp heavy cream before adding the cheese.
If you want, I can also give a super quick 20-minute keto version that still gets rich caramelized onion flavor without the long simmer—perfect for weeknights. Do you want that?