Indulge in the Richness of Homemade Classic French Onion Soup

Caramelizing the Onions

Begin by heating the butter and olive oil together in a large, heavy‑bottomed pot over medium heat. Add the sliced onions, stirring to coat them evenly. Reduce the heat to low and let the onions sweat, stirring occasionally. After about 10 minutes, increase the temperature slightly and continue to cook, stirring every few minutes, until the onions turn a deep, glossy amber—this usually takes 35‑40 minutes. Patience here is key; the slow caramelization develops the soup’s signature sweetness.

Deglazing and Building the Broth

1. Deglaze with Wine. Pour the white wine into the pot, scraping the browned bits from the bottom with a wooden spoon. Let the wine reduce by half, about 3‑4 minutes, which concentrates its flavor and removes any raw alcohol taste.
2. Add Broth and Herbs. Stir in the beef (or vegetable) broth, fresh thyme, and bay leaf. Bring the mixture to a gentle boil, then lower to a simmer. Allow the soup to cook uncovered for 20‑25 minutes so the flavors meld and the onions become ultra‑tender.
3. Season. Taste the broth and season with salt and freshly ground black pepper. Remember that the cheese topping will add saltiness, so season conservatively at this stage.

Assembling and Baking

While the soup simmers, preheat your oven’s broiler to high. Arrange the baguette slices on a baking sheet and toast them for 2‑3 minutes per side until lightly golden. Transfer the hot soup into oven‑safe bowls, place a toasted baguette slice on top of each, and sprinkle a generous handful of grated Gruyère over the bread. Place the bowls under the broiler for 3‑5 minutes, watching closely, until the cheese bubbles and turns a deep, caramelized brown. Remove carefully, let cool for a minute, then serve piping hot.