Bring 6 quarts water and 2 teaspoons salt to a boil in a large stockpot. Stir in campanelle pasta; partially cover, and return to a boil, stirring frequently. Cook 6 minutes or until pasta is almost al dente, stirring occasionally. Drain pasta in a colander over a bowl, reserving 1 cup cooking water.
While pasta cooks, heat oil in a Dutch oven over medium-high heat. Add onion, bay leaves, and prosciutto; sauté 5 minutes or until onion softens. Add peppers, and sauté 1 minute. Stir in reserved 1 cup cooking water and tomatoes; bring to a boil. Reduce heat, and simmer 10 minutes or until sauce thickens. Discard bay leaves.
Add pasta to Dutch oven; cook 1 minute, stirring well to coat, or until pasta is al dente. Remove from heat; stir in cheese.