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A white crock of French onion soup under bubbling, browned Gruyère and toasted baguette, with extra toast, cayenne and thyme on a butcher-block counter
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Spicy French Onion Soup

Sweet onions cooked low and slow until deep brown, simmered with red wine, beef and chicken stock and a little cayenne, then topped with toasted baguette and broiled Gruyère.
Course Soup
Keyword Cayenne Pepper
Prep Time 15 minutes
Cook Time 1 hour 50 minutes
Total Time 2 hours 5 minutes
Servings 2 bowls
Calories 729kcal

Ingredients

  • 2 large sweet onions halved and thinly sliced
  • 1 tablespoon butter
  • 1 teaspoon all-purpose flour
  • 1/3 cup dry red wine
  • 1/2 teaspoon cayenne pepper powder
  • 1 teaspoon lemon juice
  • 1 teaspoon fresh thyme leaves
  • 1 bay leaf
  • 1 1/4 cups beef stock
  • 1 1/2 cups chicken stock
  • Salt and black pepper to taste
  • 1 baguette sliced 1/2 inch thick
  • 1/2 cup Gruyère cheese grated
  • 1 tablespoon Parmesan cheese grated
  • fresh parsley chopped, for garnish (optional)

Instructions

  • In a large saucepan or soup pot, melt the butter over medium-low heat.
  • Add the onions with a pinch of salt and pepper and stir to coat them in butter. Cover and cook for 15 minutes, until they soften and release their liquid.
  • Uncover and keep cooking over medium-low heat, stirring every 10 to 15 minutes, until the onions are deep golden brown and jammy, about 60 to 75 minutes more. If they start to stick or scorch, lower the heat and add a splash of water.
  • Raise the heat to medium. Sprinkle in the flour and stir for 1 minute to coat the onions.
  • Pour in the red wine and stir, scraping up the browned bits from the bottom and sides of the pan.
  • Add the cayenne, lemon juice, thyme and bay leaf, then the beef and chicken stocks. Bring to a boil, then lower the heat and simmer for 10 minutes. Remove the bay leaf and season with salt and pepper to taste.
  • Meanwhile, heat the broiler to high. Toast the baguette slices under it for 1 to 2 minutes per side, until lightly golden.
  • Ladle the soup into oven-safe bowls set on a baking sheet. Top each with a slice of toasted baguette, then the Gruyère and Parmesan.
  • Broil for 2 to 4 minutes, watching closely, until the cheese is melted, bubbling and browned in spots. Garnish with parsley if you like and serve right away, warning everyone that the bowls are hot.

Notes

Heat: Half a teaspoon of cayenne (30,000 to 50,000 Scoville heat units) gives the pot a gentle, slow warmth. For more, add up to another 1/4 teaspoon with the stock, or pass hot sauce at the table.
The onions: Don't rush them with high heat. Low and slow is what turns them deep brown and sweet without burning.
Make ahead: The soup keeps in the fridge for 3 to 4 days. Reheat it on the stove, then top and broil just before serving.
No oven-safe bowls? Melt the cheese on the toasted baguette slices on a baking sheet under the broiler, then float them on the hot soup.

Nutrition

Calories: 729kcal | Carbohydrates: 97g | Protein: 30g | Fat: 22g | Saturated Fat: 11g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 6g | Trans Fat: 0.2g | Cholesterol: 50mg | Sodium: 1623mg | Potassium: 1061mg | Fiber: 6g | Sugar: 26g | Vitamin A: 745IU | Vitamin C: 19mg | Calcium: 451mg | Iron: 6mg