Description

French Onion Soup is proof that patience turns simple ingredients into something extraordinary. Humble onions slowly transform into deep, mahogany sweetness, swimming in a savory broth and crowned with toasted bread and bubbling cheese. It’s comfort food at its finest.

Ingredients

Scale

Onion Base

4 large yellow onions, thinly sliced
3 tablespoons butter
1 tablespoon olive oil
1 teaspoon granulated sugar
1 teaspoon salt

Soup

4 cups beef broth
2 cups chicken broth
½ cup dry white wine (optional, see note)
1 teaspoon Worcestershire sauce
1 bay leaf
1 teaspoon dried thyme (or 3–4 fresh sprigs)
Black pepper, to taste

Topping

1 baguette, sliced and toasted
1½ cups shredded Gruyère cheese

Wine Substitute:
If skipping wine, add an extra ½ cup broth and finish with a small splash of apple cider vinegar or lemon juice for brightness.

Instructions

1. Start the Onions

Add sliced onions directly to the slow cooker. Dot with butter, drizzle with olive oil, and sprinkle with sugar and salt. Toss well to coat evenly.

2. Slow Cooker Caramelization

Cover and cook:

HIGH: 8–10 hours
LOW: 10–12 hours

Onions are ready when deeply golden-brown, very soft, and reduced significantly. Stir once or twice if you’re home, but it’s optional.

3. Build the Soup

Add beef broth, chicken broth, wine (if using), Worcestershire, thyme, and bay leaf. Stir well, scraping up any flavorful bits.

Cover and cook on LOW for 2 more hours to let flavors meld.

Remove bay leaf and thyme sprigs before serving.

4. Toast & Melt

About 30 minutes before serving:

Toast baguette slices until crisp
Preheat broiler

Ladle soup into oven-safe bowls. Top each with toasted bread and a generous handful of Gruyère. Place bowls on a baking sheet and broil 2–4 minutes, watching closely, until cheese is bubbly and golden.

Serving Suggestions

Serve immediately—bowls will be hot
Pair with a crisp green salad and vinaigrette
Enjoy with a glass of dry white wine or light Pinot Noir
Perfect for cozy nights, dinner parties, or holiday starters

Notes

Bistro Style: Add 1 tablespoon cognac or brandy with the wine
Mushroom Onion Soup: Add 8 oz sliced cremini mushrooms with onions
Vegetarian: Use vegetable broth and vegan butter; skip Worcestershire
Beer Version: Swap wine for stout or porter; top with cheddar + Gruyère