Place an oven rack in the center of the oven. Preheat the oven to 350 degrees F. Butter the bottom and sides of a 9-inch diameter nonstick spring form pan. Set aside.
Bring a large pot of salted water to a boil over high heat. Add the pasta and cook until tender but still firm to the bite, stirring occasionally, 4 to 5 minutes. Drain well and place in a large bowl. Add 4 tablespoons butter, 1 cup Parmesan, eggs, parsley, salt and pepper. Toss well until coated.
Sprinkle 1/4 cup breadcrumbs in the bottom of the prepared pan. Spread 1/3 of the seasoned pasta on top. Arrange half of the prosciutto in a single layer on top. Sprinkle half of the mozzarella on top. Add 1/3 of the pasta and push down lightly to form an even layer. Repeat the layers with 1/4 cup breadcrumbs, the remaining pasta, prosciutto, and mozzarella. In a small bowl, mix the remaining 1/2 cup breadcrumbs and Parmesan together. Sprinkle over the layers and dot with the remaining 2 tablespoons butter. Drizzle with olive oil and bake until light golden on top, 45 to 50 minutes. Cool for 10 minutes.
Remove the sides of the pan and cut the pasta into wedges. Serve with warm marinara sauce.