French Onion Soup (Cozy, Cheesy, Restaurant-Style)

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French onion soup with caramelized onions, toasted bread, and melted cheese

A bowl of French onion soup with deeply caramelized onions, rich broth, toasted bread, and a thick layer of melted cheese browned on top.
French onion soup is cozy, rich, and totally worth the slow caramelized onions. You get a savory, slightly sweet broth packed with deep onion flavor, then a toasty bread cap with melty cheese that turns golden and bubbly. This French onion soup recipe tastes like a restaurant classic, but you can make it right at home.

Introduction

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Caramelizing onions takes patience, but it’s mostly hands-off. You stir now and then, and the onions slowly turn golden, then deep brown and jammy. That’s where the magic happens.

The best tip? Don’t rush the onions with high heat. Low and steady gives you sweet, rich flavor without burning. Once the broth simmers, everything tastes like it cooked all day.

Why You’ll Love This French Onion Soup

  • Restaurant-style at home: That deep onion flavor and cheesy top hits the spot.
  • Cozy and comforting: Perfect for chilly nights.
  • Simple ingredients: Mostly onions, broth, and cheese.
  • Great for gatherings: Feels fancy but is very doable.
  • Make-ahead friendly: The soup base tastes even better the next day.

Ingredients for French Onion Soup

Image: A counter setup with sliced onions, butter, thyme, broth, baguette slices, cheese, and a small bowl of flour for thickening.

Ingredients for French onion soup including sliced onions, broth, bread, and cheese
Onions, broth, bread, and cheese—classic French onion soup basics

Soup Base

  • Yellow onions (4 large, thinly sliced): The star; sweet onions work too.
  • Butter (4 Tbsp): Helps caramelize; use half butter half oil if you like.
  • Olive oil (1 Tbsp): Raises smoke point so onions don’t burn.
  • Flour (1 Tbsp): Lightly thickens the broth; optional but helps body.
  • Beef broth (8 cups, low-sodium): Classic rich base; use a mix of beef and chicken broth if you want lighter.
  • Thyme (1 tsp dried or a few fresh sprigs): Adds classic herb flavor.
  • Bay leaf (1): Subtle depth.
  • Salt (to taste) and black pepper (1/2 tsp): Season at the end.

Topping

  • Baguette slices (8): Toasted and sturdy; any crusty bread works.
  • Shredded cheese (2 cups): Gruyere is classic; Swiss or mozzarella can work too.

How to Make French Onion Soup

Image: A four-panel collage showing onions caramelizing, broth simmering, soup in bowls with bread, and cheese melting under broiler.

Four-step collage showing caramelizing onions, simmering soup, adding bread, and melting cheese
Caramelize the onions, simmer the broth, then broil with bread and cheese

French Onion Soup Recipe Step-by-Step

  • 1. Caramelize the onions.

Melt butter with olive oil in a large pot over medium. Add onions and a pinch of salt. Cook 35–45 minutes, stirring every few minutes, until deep golden brown and jammy. If the pot looks dry, add a tiny splash of water and scrape up the browned bits.

  • 2. Add flour for body.

Sprinkle flour over the onions and stir for 1 minute. This gives the broth a little extra richness.

  • 3. Simmer the soup.

Pour in broth, add thyme and bay leaf, and bring to a gentle simmer. Simmer 20 minutes. Taste and season with salt and pepper.

  • 4. Toast the bread.

While soup simmers, toast baguette slices at 400°F for 6–8 minutes until crisp.

  • 5. Broil with cheese.

Ladle soup into oven-safe bowls. Top each with toasted bread and a generous handful of cheese. Broil 1–3 minutes until melted and browned (watch closely).

Tips for Perfect French Onion Soup

  • Go slow on onions: Low and steady caramelization is the key.
  • Stir and scrape: Those browned bits add flavor.
  • Season at the end: Broth reduces, so taste before adding extra salt.
  • Use sturdy bread: Prevents soggy topping.
  • Broil carefully: Cheese browns fast.

Variations & Substitutions

  • Lighter broth: Use half beef broth, half chicken broth.
  • Extra herbs: Add a pinch of rosemary.
  • No flour: Skip it for a thinner, clear broth.
  • Extra cheesy: Add a second layer of cheese on top.

Storing & Reheating

  • Fridge: Store soup base 4 days.
  • Reheat: Warm on the stove over medium-low.
  • Make-ahead: Prep soup base ahead; add bread and cheese right before serving.
  • Freeze: Freeze soup base up to 2 months (without bread and cheese).

Serving Suggestions & Pairings

  • Simple green salad
  • Roast chicken pieces or a sandwich
  • Crisp apples or grapes for a fresh contrast

Reader Review

“The onions turned out perfectly caramelized and the cheesy top was unreal. This tasted like a bistro soup!”

Final Notes

If you make this French onion soup, leave a rating and tell me—are you team extra cheese or extra bread?

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