A new twist on a traditional holiday and potluck favorite.
- 6 tablespoons butter, divided
- 1 medium onion, cut into 1/4–inch dice
- 1 red bell pepper, seeded, cut into 1/2–inch dice
- 1 pound button mushrooms, quartered
- 2 teaspoons salt
- 1/2 teaspoon freshly ground pepper
- 1-1/2 pounds fresh green beans, trimmed, cut into 2-inch pieces
- 6 tablespoons all-purpose flour
- 2 cups milk
- Pinch cayenne pepper
- Pinch nutmeg
- 1 cup grated Parmesan cheese
- 1/4 cup breadcrumbs
- 1/4 cup vegetable oil
- 4 shallots, cut crosswise in 1/4–inch pieces
Melt 2 tablespoons butter in large skillet over medium heat. Add onion and cook until almost softened. Add bell pepper and mushrooms; cook until softened. Season with 1 teaspoon salt and 1/4 teaspoon pepper. Set aside to cool.
Bring saucepan of water to a boil. Add beans and cook until just tender, 3 to 4 minutes. Drain and plunge into ice bath to stop cooking. Drain and toss with mushroom mixture.
Melt 4 tablespoons butter in a medium saucepan over medium heat. Add 1/4 cup flour; whisk constantly until golden. Pour in milk and continue whisking until mixture has thickened. Stir in cayenne, nutmeg, remaining teaspoon salt and 1/4 teaspoon pepper. Remove from heat. Pour over bean mixture and toss to combine.
Spread half the green bean mixture on the bottom of a buttered 9” x 13” pan. Sprinkle with half the grated cheese and top with the remaining half green bean mixture. Combine the remaining Parmesan and breadcrumbs, and sprinkle over the top of the casserole.
Heat oil in a skillet and toss shallot rings with remaining flour. Fry shallots in batches, turning frequently until golden brown. Transfer to paper towels to drain. Place in airtight container until ready to serve.
Heat broiler. Position covered casserole about 8 inches from heat. Cook until mixture is bubbly and heated through. Uncover and cook until top is golden brown. Sprinkle with shallots and serve immediately.