1 lb. small or medium pasta shells
5 tbsp. unsalted butter, divided
1 cup heavy cream
8 oz. Fontina cheese, shredded
Pinch of grated nutmeg
1/3 cup panko bread crumbs
¼ cup freshly grated Parmesan cheese
Preheat the oven to 400˚ F. In a large pot of boiling salted water, cook the pasta according to the package directions just until 1-2 minutes shy of al dente.
Meanwhile, dice 4 tablespoons of the butter and place in a large mixing bowl. Warm the cream in a small saucepan or the microwave. Cover to keep warm.
Once the pasta is cooked, add to the bowl with the butter and toss to coat well. Stir in the warm cream and the Fontina until the cheese starts to melt. Mix in salt to taste, and add the nutmeg.
Pour the mixture into a buttered 2-quart casserole dish. In a small bowl, melt the remaining 1 tablespoon of butter. Mix in the panko breadcrumbs and shredded Parmesan. Toss with a fork to coat evenly with the butter. Sprinkle the bread crumb mixture evenly over the pasta in the baking dish.
Bake until the sauce is bubbling and the topping turns golden brown, about 20 minutes. Serve immediately.