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Frequently paired with
The best thing to pair and share with French Onion
Ingredients
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Onion Soup
Crostini & Topping
Method
Onion Soup
Caramelize the onions
Melt the butter with the olive oil in a large, heavy-bottomed pot over medium heat. Add the sliced onions, salt, and pepper. Cook, stirring every few minutes, until the onions begin to soften, about 10 minutes.
Lower the heat to medium-low and continue to cook the onions slowly. Sprinkle the sugar over the onions to encourage caramelization. Stir frequently and scrape browned bits from the bottom. Continue cooking for 30–40 minutes total, until the onions are deeply golden-brown and sweet. If onions stick or color too quickly, reduce heat.
Deglaze and build the soup
Stir in the flour and cook 1–2 minutes to remove the raw taste. Pour in the white wine (if using) to deglaze the pan, scraping up browned bits; simmer 2–3 minutes to reduce slightly. Add the beef stock and the optional bouillon or demi-glace, then add thyme sprigs and bay leaf. Bring to a gentle simmer, then reduce heat and simmer for 20 minutes, partially covered, to meld flavors.
Taste and adjust seasoning with additional salt and pepper as needed. Remove and discard thyme sprigs and bay leaf before serving.
Crostini & Assembly
Prepare the crostini
Preheat the oven to 400°F (200°C). Arrange baguette slices on a baking sheet. Brush both sides lightly with olive oil. Toast in the oven until golden and crisp, about 6–8 minutes, flipping once halfway. Remove and rub the top of each warm toast with the cut side of the garlic clove for a hint of garlic flavor.
Assemble and broil
Ladle the hot onion soup into oven-safe bowls. Place one or two crostini on top of each bowl of soup (or serve crostini on the side). Heap a generous 1/3 to 1/2 cup of grated Swiss cheese over each crostini so it overlaps into the soup, or sprinkle cheese directly on top of the soup if you prefer a melted cap. Place bowls on a baking sheet and broil in the oven on high until the cheese is fully melted and bubbly and lightly browned, about 2–4 minutes — watch closely to avoid burning.
