Preheat oven to 325°F.
Slice off top of each tomato. Place in a glass baking dish. Sprinkle lightly with salt.
Combine hazelnuts, bread crumbs, parsley, Parmesan cheese and olive oil in a small bowl. Top each tomato with some of the bread crumb mixture. Drizzle with olive oil.
Top with a slice of Fontina cheese and bake for 30 minutes.