-
1
Melt 2 tablespoons butter in a large skillet over medium heat.
-
2
Add onion, and cook, stirring occasionally, until beginning to soften, about 4 minutes.
-
3
Add bell pepper and mushrooms, and cook, stirring occasionally, until softened and most of the liquid has evaporated, 8 to 10 minutes.
-
4
Season with 1 teaspoon salt and 1/4 teaspoon black pepper.
-
5
Remove from heat.
-
6
Let cool completely.
-
7
Bring a medium saucepan of water to a boil.
-
8
Add beans; cook until bright green and just tender, 4 to 5 minutes.
-
9
Drain, and plunge into an ice-water bath to stop cooking.
-
10
Drain beans, and dry.
-
11
Toss with mushroom mixture; set aside.
-
12
Melt the remaining 4 tablespoons butter in a medium saucepan over medium heat.
-
13
Add 1/4 cup flour; whisk constantly until mixture begins to turn golden, about 2 minutes.
-
14
Pour in milk; continue whisking until mixture thickens, 4 to 6 minutes.
-
15
Stir in cayenne, nutmeg, and remaining teaspoon salt and 1/4 teaspoon black pepper.
-
16
Remove from heat; let cool completely, stirring occasionally.
-
17
Pour over bean mixture, and toss.
-
18
Butter a 13 x 9-inch baking dish.
-
19
Spread half of the bean mixture into dish.
-
20
Sprinkle with half of the Parmesan, and then top with remaining bean mixture.
-
21
Combine remaining Parmesan and bread crumbs; sprinkle over top.
-
22
Cover with foil, and refrigerate until ready to serve (up to 1 day); bring to room temperature before heating.
-
23
Heat oil in a medium skillet over medium-high heat.
-
24
Toss shallots with remaining 2 tablespoons flour.
-
25
Fry shallots in 2 batches, turning frequently, until golden brown, about 3 minutes.
-
26
Using a slotted spoon, transfer shallots to paper towels to drain; let cool completely.
-
27
The shallots can be stored in an airtight container at room temperature up to 1 day.
-
28
Preheat the broiler, with rack about 8 inches from heat.
-
29
Cook casserole, covered, until mixture is bubbling and heated through, about 10 minutes.
-
30
Uncover, and cook until top is golden brown, about 30 seconds.
-
31
Remove from oven.
-
32
Sprinkle with fried shallots.
-
33
Serve immediately.