Combine all ingredients in a medium saucepan and simmer on medium heat about 5 minutes or until vegetables are soft, stirring frequently.
Using a handheld blender, puree the sauce to remove the chunks. If you do not have an immersion blender, you can let the sauce cool for a few minutes then puree in a blender or food processor. If the sauce is too watery, you can strain out some of the extra liquid, but be sure not to drain too much as the sauce will thicken a little more as it cools.
Storing sauce in an airtight container upside down in the refrigerator may help the sauce to last longer! Serve this sauce over noodles and chicken nuggets with some mozzarella cheese for my Chicken Nugget Parmesan recipe!