Ingredients
- 4-5 large sweet onions (Vidalia or Walla Walla are great) sliced thinly
- 4 tablespoons unsalted butter
- 2 tablespoons olive oil
- 1 teaspoon brown sugar
- 1 tablespoon gluten-free all-purpose flour
- 1/2 cup dry white wine (Sauvignon Blanc works well)
- 1/2 cup dry sherry
- 6 cups gluten-free beef broth
- 2 cups gluten-free chicken broth (optional, can use all beef broth)
- 1 sprig fresh thyme
- 1 bay leaf
- Salt and freshly ground black pepper
- 1 gluten-free baguette
- 1 cup shredded Gruyère cheese
- 1/2 cup shredded Swiss or Provolone cheese
Instructions
1. Caramelize the onions
- In a large Dutch oven or heavy-bottomed pot, melt the butter and olive oil over medium heat.
- Add the sliced onions and a generous pinch of salt. Stir to coat.
- Cover the pot and cook for 15 minutes, stirring occasionally, until the onions begin to soften.
- Remove the lid, add the brown sugar, and continue cooking uncovered for 30-45 minutes, stirring every 5-10 minutes. Cook until onions are deeply caramelized and a rich brown color.
2. Build the soup base
- Sprinkle the gluten-free flour over the caramelized onions and stir to coat. Cook for 1-2 minutes to eliminate the raw flour taste.
- Slowly deglaze the pot with the white wine and sherry, scraping up any browned bits from the bottom.
- Add the beef broth (and chicken broth, if using), thyme, bay leaf, salt, and pepper to taste. Bring to a simmer.
- Reduce heat to low, partially cover the pot, and simmer for 30-45 minutes to allow the flavors to meld.
3. Prepare the croutons
- Preheat your oven’s broiler to high.
- Slice the gluten-free baguette into rounds about ½ inch thick.
- Lightly toast the rounds under the broiler, watching closely to prevent burning.
4. Assemble and serve
- Remove the thyme sprig and bay leaf from the soup. Adjust seasonings if needed.
- Ladle the hot soup into oven-safe bowls or ramekins.
- Top each bowl with a toasted baguette slice.
- Sprinkle generously with the Gruyère and Swiss/Provolone cheese.
- Broil for 2-3 minutes, or until the cheese is melted and bubbly.
- Serve immediately and enjoy!
Expert Tips
Onion choice matters: Sweet onions are essential for the classic flavor.
Slow and steady caramelization: Don’t rush the onion-cooking process. Low and slow is the key to that deep, rich flavor.
Gluten-free substitutes: Ensure your flour, broths, and bread are certified gluten-free.
Cheese variations: Feel free to experiment with other melting cheeses like mozzarella or fontina.
Make ahead: The soup base can be made a day or two in advance and reheated before serving.
