2cupskale or spinachstripped and chopped into small pieces
In a large saucepan, add onion and cook until translucent. (It's best to pre-heat your pan, which will help the onion not stick.) Add 2-3 Tbsp. water or broth if needed to keep the onion from sticking.
Once the onion is cooked through, add the rest of the ingredients.
Bring the marinara sauce to a low boil, then simmer for 15-20 minutes. Stirring occasionally.
The sauce is ready to use however you'd like. Store and leftovers in the refrigerator for up to 1 week.