In a large mixing bowl, place 2 1/2 cups squash, 1 cup bread crumbs, sage, eggs, grated cheese, mascarpone, nutmeg, salt and pepper and stir to blend well. Dust the spring form pan with bread crumbs and pour in batter. Bake 35 to 45 minutes, or until set and a toothpick exits cleanly. Remove and let cool 20 minutes. Unmold on to plate and serve hot or cold.