Name: Proper Chophouses FRENCH ONION SOUP Recipe
Cook time: 2 h
Total time: 2 h
Yield: 6 servings
Cuisine: French
Ingredients: 2 tbs unsalted butter; 1 tbs olive oil; 6 cups yellow onions, thinly sliced (about 1/4" thick); 2 tbs shallots, thinly sliced; 1 tsp granulated sugar; 1 tbs all-purpose flour; 1 cup dry white wine (or dry sherry); 8 cups beef stock (preferably low-sodium, or combination beef/chicken); 2 each bay leaves; 3 each fresh thyme sprigs; 1 tsp Worcestershire sauce; 1 tsp salt; 1 tsp black pepper, freshly ground; 6 each bone marrow (beef bones, roasted and marrow removed from 6-8 bones); 1 each baguette, sliced 1/2" on the bias; 2 tbs extra-virgin olive oil; 1 tsp sea salt; 2 tbs fresh parsley, finely chopped; 1 tsp lemon zest; 2 cups Gruyère cheese, grated; 1 tbs Parmesan cheese, finely grated (optional, for extra umami)

Method

Broth & Soup Base

Caramelize onions

In a large heavy-bottomed pot or Dutch oven, heat the butter and 1 tablespoon olive oil over medium heat. Add the sliced onions and shallots, stir to coat. Cook, stirring every 3–5 minutes, until softened and translucent (about 15 minutes). Sprinkle the sugar over the onions to encourage browning, reduce heat to medium-low and continue to cook, stirring frequently, until deep golden-brown and concentrated in flavor (another 30–40 minutes). Adjust heat as needed to prevent burning.

Deglaze & thicken

Raise heat to medium-high and sprinkle the flour over the caramelized onions; cook 1–2 minutes, stirring constantly to remove raw flour taste. Pour in the white wine to deglaze, scraping up browned bits from the pot. Let wine reduce by about half (2–4 minutes).

Simmer soup

Add the beef stock, bay leaves, thyme sprigs, Worcestershire sauce, salt and pepper. Bring to a gentle simmer, then reduce heat to low and simmer uncovered for 20–30 minutes to meld flavors. Taste and adjust seasoning with additional salt and pepper if needed. Remove and discard bay leaves and thyme stems (leave small thyme leaves if desired). Keep the soup hot while preparing crostini.

Bone Marrow Crostini

Roast marrow (if marrow not pre-roasted)

Preheat oven to 450°F (230°C). Place marrow bones upright or cut-side up in a rimmed baking sheet, sprinkle lightly with sea salt and roast until marrow is soft and bubbling but not separated from the bone, 12–18 minutes depending on size. Remove and let cool briefly. Using a small spoon or melon baller, scoop the marrow into a small bowl. If marrow is already removed, warm gently until spreadable.

Toast baguette slices

Brush both sides of baguette slices with extra-virgin olive oil and arrange on a baking sheet. Toast in 375°F (190°C) oven or under broiler until golden and crisp, about 6–8 minutes in oven, flipping once; watch closely under broiler (1–2 minutes per side).

Assemble crostini

While toasts are warm, spread about 1–1½ teaspoons of warm bone marrow on each slice. Sprinkle each with a pinch of sea salt, then top with a light dusting of chopped parsley and a little lemon zest to cut richness. Keep crostini warm (or reheat briefly before serving).

Cheese & Final Assembly

Ladle and top

Preheat broiler. Ladle hot French onion soup into oven-safe bowls. Float one or two marrow crostini on top of each bowl or set them on a sheet to be topped separately. Generously pile grated Gruyère (and optional Parmesan) over each bowl so the cheese covers the rim of the bowl and the crostini if placed on top.

Broil to gratin

Place bowls on a baking sheet and broil until cheese is thoroughly melted, bubbling and golden brown in spots, 2–4 minutes depending on broiler strength. Watch constantly to avoid burning.

Serve

Remove from oven carefully. Garnish with a small extra sprinkle of chopped parsley if desired. Serve immediately with an extra bone marrow crostini on the side for spreading. Caution: bowls and soup will be very hot.

French Onion Soup Recipe