French onion soup is a timeless classic that has been loved for generations. Built on a base of slowly caramelized onions and a savory broth, it’s finished with the irresistible pairing of toasted bread and melted cheese. Simple yet deeply flavorful, this dish is perfect whenever you’re craving something warm and satisfying.
Ingredients
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10 medium onions, thinly sliced
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4 garlic cloves, minced
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2 Tbsp olive oil + 1 Tbsp butter (for frying)
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1 tsp sea salt (or salt of choice)
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½ tsp black pepper
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1 Tbsp Dijon mustard (plus extra for bread)
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2 bay leaves
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1 Tbsp balsamic vinegar
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33 oz (about 4 cups) vegetable or beef stock
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4 sprigs fresh thyme
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1.8 oz total mixed cheese (Emmental, Gruyère, Parmesan – or use one)
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4 slices whole-grain bread
Instructions
1. Caramelize the Onions
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Heat olive oil and butter in a large saucepan over medium heat.
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Add sliced onions and cook for 5 minutes, until softened.
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Stir in garlic, thyme, bay leaves, salt, and pepper.
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Lower heat and cook 30 minutes, uncovered, stirring occasionally, until onions turn deep golden brown.
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If onions haven’t caramelized, increase heat slightly and cook for 5 more minutes, stirring often.
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2. Build the Broth
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Stir in Dijon mustard, balsamic vinegar, and stock.
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Bring to a boil, then cover and reduce heat to low.
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Simmer gently for 15–20 minutes.
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Turn off heat and let sit for a few minutes to allow flavors to infuse.
3. Prepare the Cheese Toasts
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Toast bread slices on one side until golden.
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Flip, spread lightly with Dijon mustard, and top with cheese.
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Place under the broiler for 1 minute, until cheese melts and browns slightly.
4. Serve
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Ladle the hot soup into bowls.
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Place a cheesy toast on top (or serve on the side).
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Enjoy immediately while warm and comforting.
Tips & Variations
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Cheese Options: Gruyère is traditional, but Emmental and Parmesan add great flavor too.
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Healthier Twist: Use whole-grain bread for extra fiber and nutrients.
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Make Ahead: Soup base can be made a day ahead and reheated before serving. Toasts should be prepared fresh.
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Freezer Friendly: The soup (without bread) freezes well for up to 2 months. Thaw and reheat gently before serving.
