2poundsgreen beanstrimmed and cut into 2 inch pieces
6tablespoonsunsalted butterdivided, plus more for baking dish
3/4cupsliced shallots
1red pepperseeded and finely diced
8ouncessliced mushrooms
kosher salt to taste
2tablespoonsflour
1/4cupdry sherry
2cupswhole or 2% milk
1round5 1/4 ounce Boursin Cheese (I used Shallot & Chive Flavored)
1/4teaspoonfreshly ground pepper
grated zest of 1 lemon
2tablespoonfresh tarragonchopped
3/4cuppanko bread crumbs
3/4grated or shredded Parmesan cheese
3/4cupsliced almonds
Instructions
Preheat oven to 375 degrees. Butter 13 x 9 baking dish or casserole.
Bring a large pot of salted water to a boil. Prepare an ice bath (fill large enough bowl to hold green beans with cold water and ice.)
Add green beans to boiling water and cook for 5 minutes, or until tender. Drain the beans and plunge into ice bath. Add additional ice on top of green beans to help stop the cooking process. When beans are chilled, drain and set aside.
In a large heavy-bottom saucepan, melt 4 tablespoons of butter over medium-high heat. Add shallots and cook, stirring occasionally, until transparent, about 3 minutes. Add the bell pepper and mushrooms and a pinch of salt and cook, stirring occasionally, until the vegetables have softened and the mushrooms have given up their liquid, about 5 minutes. Whisk in the flour and cook, stirring for 1 minute more. Stir in the sherry, mixing well, then add milk while whisking constantly. Bring to a simmer, stirring occasionally, until thickened, about 1 minute, then cook for 3 minutes longer.
Remove from heat and whisk in the Boursin cheese, 1/2 teaspoons salt and pepper, lemon zest and tarragon. Taste and adjust seasoning with salt and pepper if needed. Add the reserved green beans and toss to combine. Transfer to the baking dish (the dish may be made up to this point 2 days ahead. Cover and refrigerate.)
To finish: In a small bowl stir together panko, Parmesan, and almonds. Melt the remaining 2 tablespoons butter and put over bread crumb mixture and toss to combine. Sprinkle topping over green beans. Bake until the topping is golden brown and the bean mixture is bubbling, about 30 minutes. Serve immediately.