French Onion Soup

This traditional French Onion Soup has warm baguettes topped with hot, melted Gruyere cheese. High quality beef broth, a splash of wine, and perfectly caramelized onions are the secrets to this classic recipe.

Prep Time15

Cook Time1 25

Total Time2 55

Course: Soup

Cuisine: French

Servings:

Calories: 509kcal

Author: Stephanie

Ingredients

4 large yellow onions, see notes for pound conversion
2 large sweet onions Vidalia
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 is key
1 beef bouillon cube or 1 tsp Better Than Bouillon
1.5 cups chicken broth
1 teaspoon Worcestershire sauce
Salt/Pepper to taste
1 baguette
3 Tablespoons olive oil optional
6 slices Gruyere cheese

US Customary - Metric

Instructions

Slice the onions into ¼-inch slices, (no thinner). They'll reduce in size quite a bit and you don’t want them to be too stringy. (Using a mandoline slicer makes this much easier).
Melt the butter in a large soup pot or dutch oven over medium-low heat. Wait until it begins to foam, this allows water to evaporate out, leaving the butter more clarified and smooth.
Add the onions and use tongs to toss and coat them in the butter. Leave them uncovered as they cook.
The onions will caramelize slowly, up to 2 hours or longer. Stir them every 10-15 minutes. As the onions caramelize, they may leave some brown residue at the bottom of the pot. Add a splash of wine and use a silicone spatula to 'clean' the bottom of the pot. Repeat as needed throughout the cooking process
When the onions are nearly done, sprinkle flour over them and cook for 2 minutes. Add any remaining wine and increase the heat to medium-high. Toss the onions more frequently. They are done when they are richly brown and sweet.
Add the beef broth, beef bouillon, chicken broth, Worcestershire sauce, bay leaves and thyme. Simmer over medium heat for 45 minutes with the lid cracked.
While the soup simmers, preheat the oven to 350° F.
Slice the baguette into ½ inch thick slices. Brush the tops with olive oil and bake for about 5 minutes.
Increase the oven temperature to 450° F. Top each baguette with cheese and bake in the oven until the cheese melts and begins to bubble and brown.
Remove the bay leaves and thyme stems. Season to taste with salt and pepper.
Ladle the warm soup into each bowl and top each of them with the warm baguettes. Serve!

Notes

You should use about 5 pounds of onions (total) for this recipe.

If you prefer not to use Wine, you can substitute 3 Tablespoons white wine vinegar + chicken or beef broth to make 3/4 cup.

Other cheese options include Comte, Emmental (Swiss), and/or Provolone.

Crock Pot Method:

Note: The stove top does come into play with this method as the heat is needed to fully caramelize the onions at the end. However this method allows you to almost fully caramelize the onions overnight without stirring.

Melt 4 Tablespoons of butter in the Crock Pot. Add the onions and toss to coat. Cook on low for 10 hours.
Melt 2 Tablespoons of butter in a large pot on the stove over medium-high heat. Wait until it begins to foam. Add the onions and cook for 10-15 minutes.
Decrease heat to medium. Add the flour and cook for 2 minutes. Add the white wine and cook for an additional 2-3 minutes. Pour in the beef broth, chicken broth, Worcestershire sauce, and add the bay leaves and thyme.
Simmer for another 45 minutes on the stove with the lid cracked. OR, transfer back to the Slow Cooker and cook for 2-3 hours on high or 4-6 hours on low.

Check out my Instant Pot version!

Nutrition