Jul 14 2026
RestaurantsTown HearthFrench Onion Soup Au Gratin Recipe

French Onion Soup Au Gratin Recipe

Inspired by Town Hearth
Time1h 30m
Serves4

gruyére & smoked provolone / it's hot!

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Ingredients

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Soup Base

Method

Soup Preparation

  1. 1

    Prepare the Onions

    Peel and thinly slice the yellow onions.

  2. 2

    Caramelize the Onions

    In a large pot, melt the unsalted butter over medium heat. Add the sliced onions and cook, stirring frequently, until the onions are caramelized and golden brown, about 30-40 minutes.

  3. 3

    Add Garlic

    Add the minced garlic and cook for an additional 2 minutes until fragrant.

  4. 4

    Deglaze with Wine

    Pour in the dry white wine and scrape the bottom of the pot to release the browned bits. Allow the wine to cook down for about 5 minutes.

  5. 5

    Simmer the Soup

    Stir in the beef broth, fresh thyme, bay leaves, salt, and black pepper. Bring the mixture to a boil, then reduce the heat and let it simmer for 30 minutes.

  6. 6

    Finalize Soup Base

    Remove the bay leaves and adjust seasoning to taste if necessary.

Assembly and Baking

  1. 7

    Preheat Oven

    Preheat the oven to 400°F (200°C).

  2. 8

    Prepare for Cheese

    Ladle the soup into oven-safe bowls. Place a slice of baguette on top of each bowl of soup.

  3. 9

    Add Cheese

    Generously sprinkle the grated Gruyère and smoked provolone cheese over the baguette slices.

  4. 10

    Bake the Soup

    Place the bowls on a baking sheet and bake in the preheated oven for 15-20 minutes, or until the cheese is bubbly and golden brown.

  5. 11

    Garnish and Serve

    Remove from the oven and let cool slightly before serving. Garnish with chopped parsley.

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