• *Preheat the oven to 375-degrees F.

For the Marinara

• In a large, deep skillet heat olive oil over medium heat. Add the onion and garlic, then lower the heat to medium low. Cook, stirring as needed, until onions are translucent and golden. If ingredients begin to stick, add a little water, stir, and continue to cook until onions are translucent.
• Add the whole tomatoes, with juice. Break up tomatoes well with a wooden spoon or other tomato breaker-upper of your choice. :)
• Stir in the tomato sauce, tomato paste, basil, oregano, and sugar. If sauce appears too thick, add about 3/4 cup water. I simply put some water in the tomato can to rinse down the sides and added that to the pan. The sauce will reduce during cooking, but don't let it get too thick.
• Add salt and pepper, to taste. Cover and cook over medium low or low heat for about 20-30 minutes, stirring as needed. Taste periodically to check for seasonings. Remember that as the sauce becomes more concentrated, it will taste saltier.
• Turn off the heat and stir in the cream. Cover and keep warm until ready to use.

For the Filling

• In a large, deep skillet, melt the butter in the oil, then add the fennel and onion. Over moderate heat, cook, stirring occasionally, until lightly browned, about 15 minutes. Add a little water as needed to keep the vegetables from scorching.
• Add the radicchio and cook until very soft, about 10 minutes. Again, add water as needed.
• If cooking liquid is present when the vegetables are done, drain cooking liquid from vegetables. Put cooked vegetables in a large mixing bowl and set aside to cool.

For the Pasta Shells

• Bring a large pot of salted water to a boil. Add pasta and cook until al dente. Do not over-cook.
• Drain. Cool under running water, then gently pat shells dry. I did not need to pat the shells dry. I simply turned each one in a colander so that the water would drain out by itself.

Finishing

• To the bowl of cooked vegetables, fold the ricotta, 1 cup of the Fontina, and the parsley. Season with salt and pepper. Taste; correct seasonings as needed. Stir in the eggs AFTER the filling has been seasoned to taste.
• Pour 1 1/2 cups of the marinara sauce into a 9- x 13-inch baking dish. Stuff each shell with a slightly rounded tablespoon of the filling. Place the shells as close together as possible on top of the sauce in the baking dish.
• Drizzle 1 cup of the remaining sauce on top. Sprinkle the remaining Fontina over the top.
• Bake for about 40 minutes, until golden. Let rest for 15 minutes. Serve the remaining sauce, warmed, on the side.