Make-Ahead Green Bean Casserole

1 . Stage

Spray a 2 1/2-quart casserole dish with cooking spray. Mince shallots until you have 3 tablespoons; slice remaining shallots into 1/8-inch rounds. Set both aside.

2 . Stage

Bring a large pot of lightly salted water to a boil. Add beans and cook until tender but still crisp, about 4 minutes. Drain, rinse, and pat dry; set aside.

3 . Stage

Melt butter in a saucepan over medium heat. Add mushrooms and cook, stirring frequently, until browned, 5 to 7 minutes. Add minced shallots and cook until softened, 2 to 3 minutes. Stir in 3 tablespoons flour, then slowly add half-and-half, broth, and soy sauce. Bring to a boil while stirring.

4 . Stage

Reduce heat to a simmer and stir until thickened, about 5 minutes. Stir in green beans and season with salt and pepper. Transfer to the prepared casserole dish, cover, and refrigerate 8 hours to overnight, or until ready to bake.

5 . Stage

Preheat the oven to 350 degrees F (175 degrees C).

6 . Stage

Remove casserole from the refrigerator and bake in the preheated oven until heated through and bubbly, about 30 minutes.

7 . Stage

While the casserole is baking, dredge shallot rings in remaining flour until evenly coated.

8 . Stage

Heat oil in a saucepan over medium heat. Lower shallots carefully into the hot oil, working in batches if necessary. Fry until golden brown, 1 to 2 minutes, then drain on paper towels.

9 . Stage

Remove casserole from the oven and top with fried shallots.