In a large skillet, heat the olive oil over medium-high heat. Add the onions and cook until they become soft (about 3-5 min). Then add the garlic and cook a minute longer. Next add in ground beef and seasonings. Cook meat until browned. Drain any excess grease.
Add in spaghetti sauce and diced tomatoes and let simmer uncovered for about 15 minutes. Season to taste.
Cook spaghetti noodles according to package while sauce is simmering.
Serve sauce over noodles while hot and add fresh basil and parmesan if desired.
Tip: For a thinner sauce, add in 1/2 cup of the pasta water before simmering.To freeze: Let cool completely, then add sauce to a freezer bag. Label with the date, then store in freezer for up to 3 months.To thaw: Let thaw in the fridge overnight, then reheat on the stove until warm. Serve over spaghetti noodles and add cheese if desired!