Onion Soup Croquette Recipe

Caramelize onions

Heat a wide skillet over medium heat. Add 1 tablespoon olive oil and 1 tablespoon butter. When butter melts, add the thinly sliced onions and a pinch of salt. Cook, stirring every few minutes, until onions are deeply golden and caramelized, about 25–30 minutes. Reduce heat if browning too quickly.

Deglaze and simmer

Add minced garlic and cook 30 seconds until fragrant. Pour in 1 tablespoon dry white wine to deglaze, scraping up brown bits. Stir in the stock, thyme leaves, bay leaf, Worcestershire sauce, salt and pepper. Bring to a simmer and cook gently 8–10 minutes to concentrate flavors. Remove bay leaf. Taste and adjust seasoning.

Reduce to concentrated soup

Continue simmering to reduce liquid slightly until mixture is thick but still saucy, about 10 minutes more. You should end with roughly 1 to 1 1/4 cups of richly flavored onion soup. Remove from heat and let cool 10 minutes.

Make a roux-thickened liaison

In a small saucepan, melt 1 tablespoon butter over medium heat. Whisk in 2 tablespoons flour and cook 1–2 minutes to eliminate raw flavor. Gradually whisk in 1 cup milk until smooth. Cook until the mixture thickens to a loose bechamel, about 3–5 minutes, stirring. Remove from heat and stir in 2 ounces softened cream cheese until smooth.

Combine onion base with binder

Fold the reduced onion soup into the béchamel/cream cheese mixture. Stir in 3 ounces grated Gruyère until melted and incorporated. Allow mixture to cool until warm but not hot, about 10 minutes.

Form croquette mix

In a mixing bowl, combine the cooled onion-cheese mixture with 1 cup cooled mashed potatoes, 1 beaten egg, and 1 tablespoon chopped parsley. Mix until homogeneous and hold together when pressed. Chill the mixture in the refrigerator for at least 20–30 minutes to firm up for shaping.

Shape croquettes

Prepare coating stations: shallow bowls with 1 cup flour (for dredging), 2 beaten eggs (egg wash), and 2 cups breadcrumbs. Using damp hands or a spoon, portion about 2 tablespoons of filling and shape into small ovals or rounds (roughly 1.5–2 inches diameter). You should get about 12–14 croquettes depending on size.

Coat croquettes

Dredge each croquette in flour, shaking off excess, dip into beaten egg, then press into breadcrumbs to coat fully. For an extra-crispy shell, double-dip: back into egg and breadcrumbs again. Place coated croquettes on a tray and chill 10 minutes to set the crumb.

Fry croquettes

Heat about 1 cup vegetable oil in a heavy skillet over medium heat until shimmering and a breadcrumb sizzles (approx. 325–350°F / 160–175°C). Fry croquettes in batches without crowding, turning once, until golden brown on all sides, 3–4 minutes per batch. Drain on paper towels and keep warm in a low oven (200°F / 90°C) if needed.

Plate croquettes, sprinkle with extra grated Gruyère while warm so it softens on top, and scatter chopped chives or parsley. Serve immediately with lemon wedges on the side for a bright contrast.