If green been casserole (you know, the kind made with canned green beans and a can of cream of mushroom soup) is a staple in your house for Thanksgiving and other festivities, try this fancied-up version, made with fresh green beans, exotic oyster mushrooms a white sauce, and a generous sprinkling of fried shallots. While this side dish might take a little longer than making the classic casserole, it’s well worth the effort – and you can make most of it in the same pan.
Prep Time: 10 minutes
Cook Time: 25 minutes
Total Time: 35 minutes
Yield: 6 to 8 servings
- 2 pounds green beans, trimmed and cut into 1-inch pieces
- Vegetable or canola oil, for frying
- 2 shallots, peeled, halved and very thinly sliced, separated into strands
- Kosher salt
- 3 tablespoons butter, divided
- 6 oz oyster mushrooms, larger pieces cut in half
- 2 tablespoons flour
- 1 1/2 cups milk, plus more as needed
- 1/3 cup parmesan cheese
- Black pepper
- 1 tablespoon minced fresh thyme or 2 teaspoons dried thyme
- Heat a large saucepan or heavy pot of salted water until boiling. Prepare an ice bath. Add the green beans and boil until crisp-tender, about 10 minutes. Drain in a colander, then transfer green beans to the ice bath.
- While the green beans are cooking, pour enough vegetable oil into a small saucepan to be about 1 1/2 inches deep. Line a plate with a few paper towels. Heat the oil until it shimmers (if you check it with a frying thermometer it should be about 350˚F to 375˚F. Test the heat of the oil by putting a shallot in it, the shallot should start bubbling and sizzling. Place a few shallots in the hot oil and let cook 30 seconds to 1 minute, until they are brown and crispy. Remove with a slotted spoon or a spider and place on the paper towel-lined plate to drain. Continue with the rest of the shallots. Sprinkle lightly with salt, set aside.
- In the saucepan that was used to cook the green beans, melt 1 tablespoon butter over medium heat and add the mushrooms. Saute until the mushrooms are tender and softened, about 5 minutes. Remove mushrooms from pan with tongs, reserving on a plate or in a bowl. Add the remaining 2 tablespoons of butter to the pan, melt over medium heat until foamy. Stir in the flour with the whisk, cook for 30 seconds until it is pasty and lightly browned. Gradually whisk in the milk, whisking until smooth after each addition. Simmer until thickened, about 4 to 5 minutes. Stir in the parmesan cheese until smooth, whisking in more milk if the sauce appears to thick. It should be the consistency of gravy, thick enough to coat a piece of green bean dipped into the sauce. Stir in the thyme and season to taste with salt and pepper. Return the mushrooms and green beans to the pan and use a large spoon or the tongs to stir and turn the vegetables until they’re coated evenly with the sauce. Heat over medium heat for 5 to 10 minutes, until the green beans and mushrooms are heated through. Transfer to a large serving dish and sprinkle with the fried shallots. Serve hot.