Preparation

• Bring 2 inches of well-salted water to a boil in a 6-quart pot. Add the haricots verts and steam, tossing occasionally, until crisp-tender, about 6 minutes. Meanwhile, set up an ice-water bath in a large bowl. Drain the haricots verts, shock them in the ice water to stop cooking, and pat dry.
• In an 8-quart heavy-duty pot, cook the bacon over medium-low heat until golden and crisp, about 8 minutes. Using a slotted spoon, transfer to a paper-towel-lined plate and set aside. Raise the heat to medium high, add the butter to the bacon fat, and cook until melted. Stir in the mushrooms, shallots, scallion whites, 1 tsp. salt, and 1/2 tsp. pepper, and cook until the mushrooms are golden brown, about 15 minutes. Add the sherry and cook until the liquid evaporates, about 2 minutes. Turn the heat down to medium low, add the haricots verts, scallion greens, and cream, and toss well. Cover and cook until heated through, about 7 minutes. Season to taste with salt and pepper. Transfer to a large serving dish, garnish with the bacon, and serve.

Make Ahead Tips

You can steam the haricots verts up to 3 days ahead and store them refrigerated.