Preheat your oven to 350º with the oven rack in the middle. On a rimmed baking sheet, roast the whole spaghetti squash (just put the entire thing on the baking sheet! No need to cut it or anything) for 1 hour, turning the squash half way through. Allow to cool for 20 minutes until cool enough to handle.

While the spaghetti squash is cooling, heat a large skillet over medium high heat. Add the olive oil, onion, sausage, salt and pepper. Cook for 10-15 minutes until the onions are soft and the sausage gets brown marks.

Using a large knife, cut the spaghetti squash in half. Use a spoon to scoop out the seeds, and throw away. Use a fork to shred the spaghetti squash into a large bowl. Add in the cooked sausage and onion, pesto sauce and nutritional yeast. Toss to combine.

Serve warm topped with fresh basil. I sometimes like to serve mine right in the spaghetti squash skin!

Leftovers will keep refrigerated in an airtight container for 1 week.