1. Fill a 4-quart kettle three-fourths full with salted (1 tablespoon) water and bring to a boil.
2. Add macaroni and cook in boiling water until al dente (follow package directions) and drain in a colander.
3. While macaroni is cooking, in a non-stick skillet heat butter over moderate heat until foam subsides.
4. Add bread crumbs, sage, and salt and pepper to taste.
5. Cook bread crumb mixture, stirring, until golden brown, about 3 minutes.
5. In a large bowl, stir together mascarpone and Parmesan.
6. Add macaroni and salt and pepper to taste. tossing to combine.
7. Divide macaroni between 2 bowls and sprinkle with seasoned bread crumbs.