If baking a spaghetti squash, preheat your oven to 400F. Slice the squash in half, scoop out the seeds in the center, and place cut-side down on a lined baking sheet. Roast at 400F for 30-45 minutes, until the shell can be easily pierced with a fork. If using traditional noodles, make the sauce first, then cook the pasta according to the directions on the package.
For the sauce, melt the coconut oil in a skillet over medium heat, and saute the onions and garlic for about 5 minutes, until tender.
Transfer the onions and garlic to a blender or food processor, and add in the pumpkin puree, almond milk, sage leaves, nutritional yeast and salt.
Blend until the sauce is smooth and creamy, and adjust seasonings to taste.
When your pasta is ready, transfer it to the skillet, heated again over medium heat, and smother it in the pumpkin sauce. Stir to combine, heating thoroughly, and season again, to taste. (I added more salt to balance out the sweet spaghetti squash noodles.)
Serve piping hot, and garnish with additional nutritional yeast and fresh sage.