In a saucepan filled with salted water on high heat, blanch the diced squash for 5 minutes or until tender. Boil pasta according to package instructions. In a frying pan over medium heat, brown the onions in the oil for two minutes, stirring. Add the sausage meat and garlic. Sauté while stirring for 5 minutes. Pour in white wine and reduce to half. Add cream and sage. Bring to a boil. In a bowl, coat pasta with sauce and add the blanched diced squash. Stir in half the cheese. Transfer to an oven-safe dish and bake on the middle rack for 8 minutes.
Remove from oven and sprinkle with the remaining cheese. Serve.