Onion Soup with Fontina

Why You’ll Love This Recipe

This soup delivers all the depth and richness of traditional French onion soup, with a luxurious upgrade thanks to Fontina cheese. Fontina melts beautifully, creating a velvety, golden topping that complements the sweet and savory caramelized onions. It’s the kind of dish that feels both rustic and indulgent, and it’s perfect whether you’re serving it as a starter or a main course with crusty bread. Easy to prepare and incredibly satisfying, this soup is sure to become a favorite.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

• Yellow onions, thinly sliced
• Butter
• Olive oil
• Garlic, minced
• Fresh thyme (or dried)
• Bay leaf
• Dry white wine
• Beef broth (or a mix of beef and chicken broth)
• Salt
• Black pepper
• Baguette slices or crusty bread
• Fontina cheese, shredded

Directions

1. In a large pot or Dutch oven, heat butter and olive oil over medium heat.
2. Add the sliced onions and cook slowly, stirring occasionally, for 30–40 minutes until deeply caramelized and golden brown.
3. Stir in the garlic, thyme, and bay leaf, cooking for another minute.
4. Deglaze the pot with white wine, scraping up any brown bits from the bottom.
5. Pour in the broth, bring to a simmer, and cook uncovered for 20–25 minutes. Season with salt and pepper to taste.
6. Meanwhile, toast the baguette slices until crisp.
7. Preheat the broiler.
8. Ladle the soup into oven-safe bowls, top each with a toasted bread slice, and generously sprinkle Fontina cheese on top.
9. Place the bowls under the broiler for 2–3 minutes, or until the cheese is melted and bubbling.
10. Serve immediately, garnished with extra thyme if desired.

Servings and timing

This recipe serves approximately 4 people.
Prep time: 10 minutes
Cook time: 1 hour
Total time: 1 hour 10 minutes

Variations

• Vegetarian Version: Use vegetable broth instead of beef broth.
• Add a Kick: Add a splash of brandy or sherry for deeper flavor.
• More Cheese: Mix in Gruyère or mozzarella with the Fontina for a more complex topping.
• Thicker Soup: Add a spoonful of flour during the last 5 minutes of caramelizing the onions to slightly thicken the broth.
• Herb Swap: Try rosemary or sage in place of thyme for a different herbal note.

Storage/Reheating

Store leftover soup (without the bread and cheese topping) in an airtight container in the refrigerator for up to 4 days.
To reheat, warm the soup on the stovetop over medium heat. Toast fresh bread and melt the cheese again under the broiler when ready to serve.
You can also freeze the soup base (without toppings) for up to 2 months.

FAQs

What makes Fontina a good cheese for onion soup?

Fontina melts smoothly and has a mild, nutty flavor that complements the savory onion broth beautifully.

Can I make this soup ahead of time?

Yes, the soup base can be made a day or two in advance and reheated before serving with fresh bread and melted cheese.

Can I use red onions instead of yellow?

You can, though yellow onions caramelize more evenly and have a sweeter flavor. Red onions will give a deeper color and a slightly sharper taste.

Is there a substitute for white wine?

Yes, you can use a splash of apple cider vinegar or lemon juice to deglaze the pot if you prefer to avoid alcohol.

What’s the best bread for topping the soup?

Baguette slices or any crusty, day-old bread work best as they hold up well under the cheese.

Can I use pre-shredded cheese?

It’s best to shred your own Fontina, as pre-shredded cheese often contains anti-caking agents that affect melting quality.

Is it necessary to broil the soup?

Broiling gives you the classic bubbly, golden cheese top, but you can melt the cheese in the oven if broiling isn’t an option.

How long should I caramelize the onions?

Caramelizing onions takes about 30–40 minutes for the best flavor and color—don’t rush it.

Can I add protein to make it more filling?

Yes, shredded chicken or browned sausage can be added to the soup for a heartier meal.

What can I serve with onion soup?

A simple green salad or roasted vegetables pair well, or serve with extra bread for dipping.

Conclusion

Onion Soup with Fontina is a deliciously elevated version of a timeless classic. With deeply caramelized onions, a rich broth, and perfectly melted cheese, it’s everything you want in a comforting bowl of soup. Whether you’re cooking for a cozy night in or entertaining guests, this recipe offers both flavor and elegance with every spoonful.

Onion Soup with Fontina

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Onion Soup with Fontina is a rich and comforting twist on classic French onion soup, featuring deeply caramelized onions in a savory broth topped with nutty, melty Fontina cheese and crusty bread.

• Author: Laura
• Prep Time: 10 minutes
• Cook Time: 1 hour
• Total Time: 1 hour 10 minutes
• Yield: 4 servings
• Category: Soup
• Method: Stovetop + Broiler
• Cuisine: French
• Diet: Vegetarian

Ingredients

• 4 large yellow onions, thinly sliced
• 2 tbsp butter
• 1 tbsp olive oil
• 2 cloves garlic, minced
• 1 tsp fresh thyme (or 1/2 tsp dried thyme)
• 1 bay leaf
• 1/2 cup dry white wine
• 4 cups beef broth (or a mix of beef and chicken broth)
• Salt, to taste
• Black pepper, to taste
• 4–6 baguette slices or crusty bread
• 1 1/2 cups Fontina cheese, shredded

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Instructions

1. In a large pot or Dutch oven, heat butter and olive oil over medium heat.
2. Add the sliced onions and cook, stirring occasionally, for 30–40 minutes until deeply caramelized and golden brown.
3. Stir in garlic, thyme, and bay leaf, and cook for 1 minute.
4. Deglaze the pot with white wine, scraping up browned bits from the bottom.
5. Add broth, bring to a simmer, and cook uncovered for 20–25 minutes. Season with salt and pepper to taste.
6. Meanwhile, toast the baguette slices until crisp.
7. Preheat the broiler.
8. Ladle the soup into oven-safe bowls. Top each with a toasted bread slice and shredded Fontina cheese.
9. Place bowls under the broiler for 2–3 minutes, until cheese is melted and bubbling.
10. Serve hot, garnished with extra thyme if desired.

Notes

• Use vegetable broth for a vegetarian version.
• Add a splash of brandy or sherry for a deeper flavor profile.
• Combine Fontina with Gruyère or mozzarella for a richer cheese blend.
• Add a spoonful of flour while caramelizing onions for a slightly thicker soup.
• Swap thyme with rosemary or sage for different herbal notes.

Nutrition

• Serving Size: 1 bowl with bread and cheese
• Calories: 420
• Sugar: 7g
• Sodium: 870mg
• Fat: 25g
• Saturated Fat: 14g
• Unsaturated Fat: 9g
• Trans Fat: 0g
• Carbohydrates: 28g
• Fiber: 3g
• Protein: 18g
• Cholesterol: 55mg