1 1/2 - 2 pounds frozen cut green beans (use fresh trimmed green beans when in season)
2 Tbs unsalted butter
10 oz sliced baby bella (the little portobella) mushrooms (see variation below)
3 Tbs minced shallots (if shallots are not available, finely diced onion works well)
1/4 cup all purpose flour
1 cup half-and-half (using milk produces a less creamy, but equally delicious result)
1 cup chicken stock (see variation below)
1 tsp soy sauce
Preheat oven to 350 F. Lightly butter a deep 2 1/2 quart baking dish. (If going the “make ahead” route skip this step.
Bring a large saucepan of salted water to a boil over high heat. Add the green beans and cook until tender-crisp, about 4 minutes. (Using a larger pot meant less of a temperature drop of the water when the frozen beans where added). Drain and rinse under cold water; allow excess water to drain off in a colander or pat dry with paper towels. Yes, the beans are being blanched. Skipping this step results in a final product in which the beans that are more of a camouflage color rather than green.
In a saucepan over medium heat melt about half of the unsalted butter. Add the sliced mushrooms until they are nicely browned and start to give off their juices. Stir in the minced shallots and cook until softened. Add the rest of the butter now (this butter, along with the juices from the mushrooms and shallots forms the basis for the sauce.) Sprinkle the vegetables with the flour and stir well. (tossing all the flour in at one spot will create lumps, so sprinkle, I'd even go as far as calling this step "dusting")
Slowly stir in the half-and-half, stock and soy sauce. While stirring often, bring the mixture to a low boil. Reduce heat and allow the mixture to simmer until thickened, about 4 minutes. Stir in the green beans. Season to taste (each time I made the dish I seasoned with only pepper and everyone loved it). Pour the entire mixture into the baking dish.
(Up to this point the entire dish can be prepared the day ahead and stored, covered in the refrigerator)
Bake the dish in the preheated 350F oven until the liquid is bubbling, about 20 minutes if going right into the oven, about 30 minutes if you made ahead and its coming from the refrigerator
In honor of Dorcas Reilly sprinkle the top with canned French Fried Onions. They were always the best part of the original recipe and making small onion rings from scratch is too much trouble for Thanksgiving.
Variations : If Baby Bellas are not available, substitute common white champignons (yes, button mushrooms have a cool name).
To really switch things up try a dried mushroom mixture instead of fresh; rehydrate the mushrooms reserving any remaining liquid to replace some of the chicken stock. This variation is uber mushroomy.