French Onion Au Gratin Recipe

Peel and thinly slice the yellow onions. Mince the garlic cloves.

Slice the baguette into 1-inch thick slices.

Sauté the Onions

In a large pot, melt 2 tablespoons of butter over medium heat. Add the sliced onions and a pinch of salt. Cook, stirring frequently, for about 20-25 minutes until the onions are caramelized and golden brown.

Add Garlic and Deglaze

Add the minced garlic to the caramelized onions and cook for an additional 2 minutes. Pour in the dry white wine, scraping the bottom of the pot to deglaze. Let it reduce by half.

Add Broth and Season

Add the beef broth, thyme, bay leaf, salt, and black pepper to the pot. Bring to a simmer and let it cook uncovered for about 15 minutes.

Stir in the Cream

Remove the bay leaf from the soup and stir in the heavy cream. Allow it to heat through for another 5 minutes.

Prepare the Topping

Preheat the oven to 375°F (190°C). In a baking dish, ladle the soup into individual oven-safe bowls. Place a slice of baguette on top of each bowl of soup.

Add Cheese

Sprinkle the Gruyère and Parmesan cheese generously over the baguette slices.

Bake

Place the bowls on a baking tray and bake in the preheated oven for about 15-20 minutes, or until the cheese is melted and bubbly.

Serve hot, garnished with additional thyme if desired.