Styling Kari Wardrop, Photography Jerry Grajewski.
In saucepan, heat 2 tablespoons extra-virgin olive oil over medium heat. Add garlic and onions and cook until translucent. Add thyme, stock, and cream; bring to boil. Mix 1/4 cup our with butter in small bowl. Remove saucepan from heat and whisk in butter flour mixture until incorporated. Return to a simmer and cook for 15 minutes, whisking constantly. Add lemon juice and season.
In large pot of salted water, blanch beans until tender, 2 to 3 minutes. Drain and chill in ice bath. Drain on paper towels.
Toss shallots with remaining our in bowl. In saucepan, heat oil to high heat and fry shallots, stirring constantly, until golden. Drain on paper towel. Season.
To serve, preheat oven to 350°F. In saucepan sauté mushrooms in 2 tablespoons oil until golden. Transfer to bowl; add cream mixture and beans. Transfer to ovenproof casserole dish and bake uncovered for 15 minutes. To serve, top with parsley and crispy shallots. Serves 8.