Add oil to a medium sized pan over medium-high heat. Add in ground beef and and cook while breaking it up until no longer pink.
Add diced onion, garlic, salt and Italian seasoning. Stir and continue to cook for about 3-4 minutes or until onions are soft. Add jar of Marinara sauce and half a cup of water. Stir and mix well. Cover with lid and simmer on low heat for 20 minutes.
If desired add roughly chopped basil and mix in. Serve on spaghetti squash for Whole 30 or on pasta! Enjoy!