French Onion Soup Recipe

Prepare onions: Peel and cut off root ends, then halve and slice each onion thinly (about 1/8-inch). Aim for uniform slices so they caramelize evenly.

Heat a large, heavy-bottomed pot or Dutch oven over medium heat. Add unsalted butter and 1 tbsp olive oil; when butter is melted and begins to shimmer, add the sliced onions in an even layer.

Cook the onions, stirring every 2–3 minutes. After about 10 minutes they will soften; reduce heat to medium-low. Sprinkle the sugar and kosher salt over the onions to encourage browning. Continue to cook, stirring more infrequently (every 4–6 minutes) so they can brown, for 35–50 minutes until deep golden-brown and richly caramelized. If they begin to stick or brown too quickly, lower the heat and add a splash of water to deglaze the pan.

When onions are deeply caramelized, add the minced garlic and cook 30–60 seconds until fragrant, taking care not to burn it.

Deglaze: Increase heat to medium-high and add the dry white wine or sherry (if using). Scrape up browned bits from the bottom of the pot and simmer until most of the liquid has evaporated, about 2–3 minutes.

Add beef stock, beef bouillon paste, thyme sprigs, bay leaves, and Worcestershire sauce. Bring to a gentle simmer, then reduce heat to low and simmer gently, uncovered, for 20–30 minutes to allow flavors to meld. Taste and adjust seasoning with salt and pepper as needed. If using the optional splash of sherry or brandy, stir it in now off the heat.

Remove thyme sprigs and bay leaves before serving.

Preheat oven to 425°F (220°C) or preheat a broiler on high if using the broil method.

Arrange baguette slices on a baking sheet. Brush each slice lightly with olive oil (and optional melted butter) on both sides. Toast in the oven for 6–8 minutes, flipping halfway, until lightly golden and crisp. Alternatively, broil 1–2 minutes per side watching closely to avoid burning.

Remove toasted bread. Place a layer of provolone on each crouton and sprinkle with grated parmesan.

To assemble individual bowls: Preheat oven to 400°F (200°C) or set broiler to high. Ladle hot soup into oven-safe bowls (leave about 1 inch headspace). Place 1–2 cheese-topped croutons on each bowl so the cheese bridges the rim, or float croutons on top of the soup and then add extra cheese over the top.

Place bowls on a baking sheet and bake at 400°F for 8–12 minutes or broil on high for 2–4 minutes until cheese is melted, bubbly, and slightly golden. Watch carefully to prevent burning.

Carefully remove hot bowls from the oven. Garnish with chopped fresh parsley and an additional sprinkle of parmesan if desired. Serve immediately with a spoon and caution: bowls will be very hot.

Storage: Refrigerate leftover soup (without cheese-topped bread) in an airtight container for up to 3–4 days. Reheat gently on the stove. Toast fresh baguette slices and add cheese when reheating for best texture.