Step 1

In a fry pan, sauté chopped onions with a drizzle of olive oil over medium heat for a few minutes until golden. Then add rest of sauce ingredients and stir. Bring the sauce to a boil, then reduce to a simmer and cook for 3-5 minutes. Sprinkle arrowroot flour into sauce and whisk until sauce thickens (do not over cook, because the sauce will become too thick), then remove from heat.

Step 2

Add cooked spaghetti squash and tuna to sauce, combine, and serve!