Description
A rich and comforting French Onion Cabbage Gratin featuring slowly caramelized onions layered with seared cabbage wedges, a creamy Gruyère sauce, and a crunchy golden breadcrumb topping. This elegant dish combines deep savory flavors and creamy textures, perfect as a hearty side or vegetarian main course.
Ingredients
Scale
Caramelized Onions
- 2 tbsp. unsalted butter
- 2 large yellow onions, thinly sliced into half-moons
- 1 tsp. kosher salt
- 2 thyme sprigs
- 1/3 cup dry white wine
- Freshly ground black pepper, to taste
Cabbage and Gratin
- 1 small head of green cabbage (about 2 lb.), cut into 6 wedges
- 1 1/4 tsp. kosher salt, divided
- 4 tbsp. unsalted butter, divided
- 1/2 cup panko breadcrumbs
- 4 tbsp. neutral oil (such as vegetable or canola), divided
- 2 tbsp. all-purpose flour
- 1 1/2 cups heavy cream
- 1 1/2 cups whole milk
- 1 1/2 cups shredded Gruyère cheese, divided
Instructions
- Caramelize the Onions: In a straight-sided, 12-inch (preferably cast-iron) skillet over medium heat, melt 2 tablespoons of unsalted butter. Add the thinly sliced onions and 1 teaspoon kosher salt, cooking and stirring occasionally for 35 to 50 minutes until the onions become deeply golden brown and jammy.
- Add Thyme and Wine: Stir in 2 sprigs of thyme and 1/3 cup dry white wine, scraping up browned bits from the pan. Cook for 1 to 2 minutes until the liquid reduces and the onions are jammy. Season with freshly ground black pepper and transfer to a clean bowl to cool. Wipe out the skillet.
- Prep the Cabbage: Arrange an oven rack in the center and preheat the oven to 350°F (175°C). Spread the cabbage wedges on a baking sheet and season all over with 1 teaspoon kosher salt. Let them sit for 10 minutes to draw out moisture.
- Toast Breadcrumbs: In a large ovenproof skillet over medium heat, melt 2 tablespoons butter. Add 1/2 cup panko breadcrumbs and season with the remaining 1/4 teaspoon kosher salt. Cook, stirring frequently, until the breadcrumbs turn golden brown, about 3 to 4 minutes. Transfer to a small bowl and wipe out the skillet.
- Sear the Cabbage: In the same skillet over medium-high heat, heat 2 tablespoons neutral oil. Pat half of the cabbage wedges dry and place them flat side down. Sear until golden brown on the bottom, about 2 to 3 minutes. Flip and cook the other flat side for an additional 2 minutes. Return the cabbage to the baking sheet and repeat with remaining 2 tablespoons oil and the remaining wedges. Wipe out the skillet again.
- Make the Sauce: Return skillet to medium heat and melt the remaining 2 tablespoons butter. Stir in 2 tablespoons flour and cook, stirring constantly, until it forms a bubbling blonde roux, about 1 minute. Slowly whisk in 1 1/2 cups heavy cream and 1 1/2 cups whole milk. Bring to a boil, then reduce heat to medium and cook, stirring occasionally, for 5 to 7 minutes until the sauce thickens slightly. Remove from heat and fold in 1 cup shredded Gruyère cheese and three-quarters of the caramelized onions.
- Assemble the Gratin: Nestle the seared cabbage wedges back into the skillet and spoon the creamy onion sauce over them. Top with the remaining caramelized onions, then sprinkle with the remaining 1/2 cup Gruyère cheese and half of the toasted breadcrumbs.
- Bake the Gratin: Transfer the skillet to the preheated oven and bake until the cabbage is tender and the gratin is bubbly and golden, about 40 minutes.
- Finish and Serve: Remove from the oven and sprinkle the remaining breadcrumbs and fresh thyme sprigs on top. Season with freshly ground black pepper to taste. Serve warm.
Notes
- Caramelized onions can be prepared up to 3 days in advance and refrigerated in an airtight container.
- Use a cast-iron skillet if possible for best heat distribution, but any ovenproof skillet will work.
- For a vegetarian version, ensure the butter and cheese used are free from animal rennet if desired.
- Leftovers reheat well in a covered dish in the oven or microwave.
- Prep Time: 20 minutes
- Cook Time: 1 hour 15 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: French
Keywords: French onion, cabbage gratin, caramelized onions, Gruyère cheese, baked cabbage, creamy gratin, vegetarian side dish
