I ended up cutting back on the fennel just a little here and added more cheese, opting for Fontal instead of Fontina, which is apparently Fontina’s less expensive (but no less delicious) cousin. And I think these shells would be great with any number of other vegetables; I love the idea of doing them with different mushrooms, greens and goat cheese. The possibilities are endless.
Lightly adapted from: Food and Wine
Preheat the oven to 375 F. In a large, deep skillet, melt the butter in the oil. Add the fennel and onion and cook over moderate heat, stirring occasionally, until lightly browned, about 15 minutes; add water as needed to keep the vegetables from scorching. Add the radicchio and cook until very soft, about 10 minutes, adding water as needed. Scoop the vegetables into a bowl and let cool.
Meanwhile, in a large pot of salted boiling water, cook the pasta al dente. Drain and cool under running water. Pat shells dry. Fold the ricotta, Fontina, and parsley into the vegetables and season with salt and pepper. Stir in the eggs.
In another bowl, mix the marinara sauce with the cream. Pour 1 cup into the 9×13-inch baking dish and swirl around a bit to coat the bottom. Stuff each shell with a heaping tablespoon of filling and nestle the shells in the sauce as close together as possible. Drizzle remaining sauce on top and sprinkle with the mozzarella. Bake the shells for about 40 minutes, or until bubbling and crisp on top. Let rest 10 minutes before serving.