Description

Classic French Onion Soup featuring slowly caramelized onions simmered in a rich beef and chicken broth, topped with toasted baguette slices and melted Gruyere cheese. This comforting and flavorful soup is perfect for cozy meals and showcases the perfect balance of sweet, savory, and cheesy goodness.

Ingredients

Scale

Onions

4 large yellow onions (about 5 pounds total)
2 large sweet onions (Vidalia)

Cooking Base

6 Tablespoons butter
2 sprigs fresh thyme
2 bay leaves
¾ cup dry white wine (Chardonnay or Pinot Grigio)
3 tablespoons flour (optional)
4 cups beef broth (high quality)
1 beef bouillon cube or 1 teaspoon Better Than Bouillon
1.5 cups chicken broth
1 teaspoon Worcestershire sauce
Salt and pepper to taste

For Topping

1 baguette
3 Tablespoons olive oil (optional)
6 slices Gruyere cheese

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Instructions

Slice the onions: Slice the onions into ¼-inch thick slices, avoiding thinner cuts to prevent stringiness. A mandoline slicer is helpful here to keep uniform thickness.
Melt butter and start caramelizing onions: Melt the butter in a large soup pot or Dutch oven over medium-low heat until it begins to foam, clarifying the butter. Add the sliced onions and toss them to coat evenly. Keep the pot uncovered as the onions slowly caramelize, stirring every 10-15 minutes for up to 2 hours or longer. To prevent burning, deglaze the bottom of the pot occasionally with splashes of white wine.
Add flour and cook onions further: When the onions are nearly caramelized, sprinkle the flour over them and cook for 2 minutes. Add the remaining white wine and increase heat to medium-high, tossing the onions frequently. Finish when onions turn richly brown and sweet.
Add broths and aromatics: Pour in the beef broth, crumble in the beef bouillon cube or add Better Than Bouillon, add the chicken broth, Worcestershire sauce, bay leaves, and fresh thyme. Bring to a simmer over medium heat with the lid cracked and cook for 45 minutes to develop flavors.
Prepare baguette slices: While the soup simmers, preheat the oven to 350° F. Slice the baguette into ½ inch thick slices. Brush the tops with olive oil if desired, then bake for about 5 minutes until slightly toasted.
Melt cheese on baguette slices: Increase oven temperature to 450° F. Top each toasted baguette slice with Gruyere cheese. Return them to the oven and bake until the cheese melts, bubbles, and browns slightly.
Final touches and serve: Remove bay leaves and thyme sprigs from the soup. Season with salt and pepper to taste. Ladle soup into bowls and top each with warm, cheesy baguette slices. Serve immediately for best flavor and texture.

Notes

The total amount of onions used should be around 5 pounds for optimal flavor and volume.
If avoiding wine, substitute 3 tablespoons white wine vinegar combined with additional chicken or beef broth to make ¾ cup liquid.
Alternative cheeses such as Comte, Emmental (Swiss), or Provolone may be used instead of Gruyere for variation.
A slow cooker method is available where onions are cooked on low for 10 hours before finishing on the stovetop to properly caramelize.
Check out the Instant Pot version for a quicker preparation option.

Nutrition

Serving Size: 1 bowl with baguette and cheese
Calories: 350
Sugar: 10g
Sodium: 900mg
Fat: 18g
Saturated Fat: 10g
Unsaturated Fat: 6g
Trans Fat: 0g
Carbohydrates: 34g
Fiber: 3g
Protein: 14g
Cholesterol: 45mg