Shallots sautéed in butter and freshly grated Parmesan cheese combine with a rustic medley of mushrooms for a satisfying vegetarian entrée. Serve with a light green salad.
Preheat oven to 450 degrees. Spray a 9-inch tart pan with cooking spray. Remove pie crust from aluminum tin and press into bottom and sides of tart pan. Prick the bottom of the crust all over with a fork then line crust with parchment paper and fill with pie weights or dried beans. Transfer pan to a rimmed baking sheet and bake for 10 minutes. Gently remove paper and beans, then sprinkle 1/2 cup of the cheese evenly over the bottom of the crust and set aside. Reduce oven temperature to 350 degrees.
Heat butter and oil in a large skillet over medium heat. Add shallots and cook until golden, about 5 minutes. Stir in mushrooms, salt and pepper and cook until soft, 6 to 8 minutes. Add sherry and broth and simmer, stirring often, until liquid has almost evaporated, 6 to 8 minutes more. Stir in crème fraîche and simmer again until liquid has almost evaporated, about 10 minutes.
Transfer contents of skillet to tart pan and spread out evenly. Sprinkle remaining 1 cup cheese over mushroom mixture, arrange pan on a baking sheet and bake until crust is golden and tart is bubbly, 35 to 45 minutes. Set aside to let rest for 10 minutes then cut into slices and serve.