This sauce is so basic is is easy to adjust. You can add extra sauteed veggies like onions, mushrooms, peppers, eggplant, zucchini and fennel.
It would also be great with your favorite (faux) meatball or sausage.
Adding a little splash of red wine at the end would intensify the flavor.
Hot pepper flakes would spice it up nicely.
If you are trying to get more veggies in, I've also added chopped spinach, carrots, and celery in the blender. No one will be able to tell the difference...just ask my kids. ;)
This sauce also freezes great so plan ahead and make a double batch.