The iconic green bean casserole is reworked with the flavors of French onion soup — caramelized onions and Gruyere cheese.
- 2 tablespoons butter
- 2 large yellow onions, thinly sliced lengthwise
- salt and ground black pepper to taste
- 1 tablespoon sherry vinegar
- 2 tablespoons butter
- 2 ½ tablespoons all-purpose flour
- 2 ½ cups milk
- 1 pinch ground nutmeg
- 1 pinch cayenne pepper to taste
- ¼ teaspoon ground thyme
- 2 tablespoons melted butter
- ⅓ cup panko bread crumbs
- 2 pounds fresh green beans, trimmed
- 4 ounces shredded Gruyere cheese, divided
- ⅓ cup grated Parmesan cheese
- 1 Preheat oven to 375 degrees F (190 degrees C). Grease a 9x13 inch casserole dish.
- 2 Heat 2 tablespoons of butter in a large skillet over medium heat. Stir the onions into the pan; cook and stir until very soft and golden brown, about 15 minutes. Stir in sherry vinegar. Transfer to a small bowl, and reserve.
- 3 In the same skillet, melt 2 more tablespoons butter. Whisk in 2 tablespoons flour. Stirring constantly, cook over medium heat until the flour smells like baked pie crust, about 3 minutes. Slowly whisk in milk, about 1/2 cup at a time, then whisk in nutmeg, cayenne pepper, and thyme. Bring to simmer, and cook until thickened, whisking constantly, 3 more minutes. Transfer to a bowl and reserve.
- 4 Melt remaining 2 tablespoons butter in clean skillet; stir in panko until all crumbs are coated; reserve.
- 5 Bring a large saucepan of salted water to a boil over medium heat, and boil beans until bright green and crisp but not raw tasting, 3 to 4 minutes. Drain very well.
- 6 Spoon half of the caramelized onions into the prepared casserole dish; top with green beans. Season with salt and black pepper. Spread reserved white sauce over the green beans; sprinkle with half of the Gruyere cheese. Top with the rest of the onions, and use the back of a spoon to push onions down into sauce and cheese. Top with the buttered panko crumbs, the remaining Gruyere, and Parmesan cheese.
- 7 Bake in the preheated oven until hot throughout and lightly browned, about 30 minutes. Let sit 10 minutes before serving.
- Calories 216.5
- Carbohydrate 18.9 g
- Cholesterol 38 mg
- Fat 13 g
- Fiber 3.7 g
- Protein 9.4 g
- Saturated Fat 7.9 g
- Sodium 195 mg
- Sugar 5.5 g