Onion Soup with Portabella Swiss Cheese Topping

Transform comfort food into gourmet dining with this Onion Soup with Portabella Swiss Cheese Topping, a hearty twist on the classic French onion soup. Slow-caramelized yellow onions are the heart of this dish, simmered in a flavorful broth of beef or vegetable stock with a touch of dry white wine, fresh thyme, and a hint of bay leaf. But the real showstopper is the topping—savory sautéed portabella mushrooms layered over crispy toasted baguette slices and crowned with a generous sprinkle of melted Swiss cheese. Broiled to perfection until bubbling and golden, this soup is a rich, savory masterpiece that's perfect for cozy nights or to impress at dinner parties. Serve it hot and watch it disappear! With savory caramelized onions, earthy mushrooms, and a gooey cheese finish, this recipe truly elevates the idea of comfort food with gourmet flair.

Nutriscore Rating: 67/100

Prep Time:20 mins

Cook Time:60 mins

Total Time:80 mins

Servings: 4

Ingredients

• 4 tablespoons unsalted butter
• 6 large yellow onions
• 1 teaspoon salt
• 1 teaspoon sugar
• 2 tablespoons all-purpose flour
• 1 cup dry white wine
• 6 cups beef or vegetable stock
• 4 sprigs fresh thyme
• 1 bay leaf
• 2 large portabella mushrooms
• 2 teaspoons olive oil
• 8 pieces baguette slices
• 1 cup Swiss cheese
• 0.5 teaspoon freshly ground black pepper

Directions

Step 1

Peel and thinly slice the yellow onions with a sharp knife or mandoline.

Step 2

In a large soup pot or Dutch oven, melt the unsalted butter over medium heat.

Step 3

Add the sliced onions to the pot, sprinkle with salt and sugar, and stir to coat them in butter.

Step 4

Cook the onions over medium-low heat, stirring occasionally, for 30-35 minutes until caramelized and golden brown.

Step 5

Sprinkle the flour over the onions, stir well to coat, and cook for 2 minutes to eliminate the raw flour taste.

Step 6

Deglaze the pot with dry white wine, scraping the bottom of the pot to release any browned bits. Simmer for 2 minutes.

Step 7

Add the beef or vegetable stock, thyme sprigs, bay leaf, and freshly ground black pepper to the pot. Stir well.

Step 8

Bring the soup to a boil, then reduce the heat to low, cover, and simmer for 20 minutes to allow flavors to meld.

Step 9

While the soup simmers, clean and thinly slice the portabella mushrooms. Heat olive oil in a skillet over medium heat.

Step 10

Add the mushrooms to the skillet and cook for 5 minutes, stirring occasionally, until tender. Remove from heat.

Step 11

Lightly toast the baguette slices under a broiler or in a toaster oven until golden brown.

Step 12

Preheat your broiler on high. Ladle the soup into oven-safe bowls and place on a baking sheet.

Step 13

Top each bowl of soup with 2 toasted baguette slices, several slices of cooked portabella mushrooms, and a sprinkle of shredded Swiss cheese.

Step 14

Broil the bowls on the prepared baking sheet for 2-3 minutes or until the cheese is melted and bubbly.

Step 15

Remove carefully from the oven, let cool slightly, and serve the soup hot. Garnish with extra thyme leaves if desired.

Nutrition Facts

Serving size	(3281.5g)

Amount per serving	% Daily Value*
Calories	2264.1

Total Fat 89.0g	0%
Saturated Fat 38.0g	0%
Polyunsaturated Fat 2.8g
Cholesterol 161.8mg	0%
Sodium 9331.4mg	0%
Total Carbohydrate 254.8g	0%
Dietary Fiber 27.6g	0%
Total Sugars 54.7g
Protein 78.1g	0%

Vitamin D 21.3IU	0%
Calcium 1418.6mg	0%
Iron 14.2mg	0%
Potassium 3121.6mg	0%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 37.6%

Protein: 14.6%

Carbs: 47.8%