From Melissa Clark, NYTimes:
A more sophisticated take on mac and cheese, this golden-topped casserole has roasted wild mushrooms for a deep, earthy character, and melted fontina for the gooey factor. You can use any kind of mushrooms here. If you can’t get wild ones (also called exotic, and most of them are actually farmed), use whatever is available. The key is to roast them until they are well browned and crisp at the edges so the flavor intensifies. Serve this as a vegetarian main course or as a rich side dish to roast chicken or meats. You can assemble the casserole the day before. Just add a few minutes onto the baking time if it’s cold from the fridge when you pop it into the oven.
Ingredients
1 pound mixed wild mushrooms, such as oyster, maitake and shiitake
3 tablespoons extra-virgin olive oil
½ teaspoon kosher salt, more as needed
½ teaspoon black pepper, plus a few grinds
2 fresh rosemary branches
½ pound orecchiette, farfalle or other short pasta
¾ cup heavy cream
½ cup fresh ricotta
5 ounces fontina cheese, grated (1 1/4 cups)
2 ounces Parmesan, grated (1/2 cup)
1 teaspoon finely chopped fresh sage
1 garlic clove, finely grated
Instructions
Step 1: Heat the oven to 450 degrees. Trim the mushrooms and cut into 1-inch pieces. Toss with the olive oil, the salt, a few grinds of pepper and the rosemary. Spread on a large baking sheet and roast, tossing once or twice, until golden brown and crisped around the edges, 15 to 18 minutes.
Step 2: Meanwhile, bring a large pot of salted water to a boil. Add the pasta and cook for at least a few minutes less than the package directs. (You want the pasta very al dente; it will finish softening in the sauce.) Drain well.
Step 3: Turn oven up to 500 degrees. In a large bowl, stir together the cream, ricotta, fontina, Parmesan, sage, pepper, garlic and a pinch of salt. Stir in the pasta and mushrooms. Arrange in a shallow 2-quart gratin dish or 9- by 13-inch pan. Bake until cheese is melted and bubbly and browned in spots, 10 to 15 minutes.