This recipe is easy and adaptable. You can easily make it vegan by using non-dairy milk and cheese. You can add vegetables and seasonings: chopped spinach, sauteed mushrooms, roasted garlic puree, grated carrots, fresh or dried herbs. It doubles and triples easily, so you can make it for a crowd. You also don't have to be super precise with measurements - a bit more or less of the main ingredients will still work out okay.
Cook pasta in boiling water until it is cooked through but not soft. (This should take between 7 and 10 minutes depending on your pasta brand.)
While pasta is cooking, preheat the oven to 350 degrees F / 180 degrees C. Lightly grease a 9x9-inch / 23x23 cm baking dish. In large mixing bowl, stir together remaining ingredients: pumpkin, milk, cheese, salt, garlic powder, onions and pepper.
Drain pasta and pour pumpkin sauce over. Stir to combine evenly, and spread in prepared baking dish. Bake for 15-20 minutes, or until cheese is melted. Serve hot.
This dish can be prepared in advance, but don't mix the pasta and sauce until you are ready to bake the dish. The pasta will absorb too much liquid from the sauce and it will be drier when baked.