Preheat oven to 400 degrees Fahrenheit.

Cut spaghetti squash in half and remove the seeds with a spoon. Rub the flesh with a bit of oil and place face-down on a lined cookie sheet. Bake for 40 minutes.

Remove, let cool for a few minutes. Use a fork to loosen the strands from the peel and flake into pieces. Set aside.

Meanwhile, heat a large pan with the oil and sauté the onions.  Add the meat and cook for a few minutes, stirring.

Add marinara sauce, about one cup of water (and sugar if using), and let cook for 30 minutes, stirring occasionally. Pour over spaghetti squash and serve.