MAKE-AHEAD FRESH GREEN BEAN CASSEROLE
* 3 tablespoons unsalted butter
* 8 ounces fresh mushrooms, caps broken into pieces, stems roughly chopped
* 1 teaspoon kosher salt
* 1/2 teaspoon black pepper
* 6 cloves garlic, minced (don’t skimp on these)
* 1/2 teaspoon dried thyme
* 1/4 cup flour
* 1-1/2 cups chicken stock or boullion
* 1/2 cup dry white wine
* 1-1/2 cups cream
* 2 tablespoons dry sherry
* Additional kosher salt and freshly ground black pepper, if needed
* 2 pounds fresh green beans, stems trimmed, broken into bite-size pieces
* 1/4 cup cornstarch
* 1 cup panko
* 2 tablespoons melted butter
* 1/2 teaspoon kosher salt
* Freshly ground pepper
* 2 cups (about 3 ounces) canned fried onions, chopped
SAUCE In a large pot or Dutch oven, melt the butter on medium heat til melted. Add the mushrooms, salt and pepper and cook for about 10 minutes, stirring often, until the mushrooms are cooked and the mushroom liquid has evaporated. Add the garlic and thyme and cook for about a minute. Sprinkle the mushrooms with flour and stir in as best you can. A tablespoon at a time, stir in the chicken stock, letting each tablespoon become absorbed before adding another. (This will take several minutes, be patient or you’ll risk a lumpy mess.) Stir in the wine and cream. Bring to a boil. Let simmer, stirring occasionally, until the sauce is thickened, about 15 minutes. Stir in the sherry. Taste the sauce and add salt and pepper, if needed. (It should be slightly salty and slightly peppery since the beans themselves are unseasoned.)
BEANS While the sauce cooks, toss the green beans and cornstarch well. Transfer to a 9x13 ceramic baking dish. Pour hot mushroom sauce over top. Gently press green beans into the sauce so that all the beans are submerged. Cool completely. Cover with plastic wrap, making sure there’s no air between the green beans and the plastic. Wrap with foil. Freeze. Do not thaw before baking.
TOPPING No more than a day before, mix the panko, butter, salt and pepper in a skillet. On medium heat, let the crumbs brown, stirring often, being careful not to burn. Stir in the fried onions.
BAKING Preheat oven to 400F. IMPORTANT: remove plastic wrap from casserole, then replace the foil. Bake for 30 minutes, stir, leave the foil off and bake for another 50 minutes. (If the sauce is too thin, leave in oven, stirring every 5 minutes or so, until it thickens.) Spread topping over the casserole, bake for another 10 minutes until golden. The green bean casserole is ready to serve....enjoy it !