Prepare zucchini and squash and add them to a large bowl.
In a small bowl, prepare sauce with all remaining ingredients except balsamic vinegar.
Add sauce to zucchini and squash and toss to coat, making sure everything is mixed and coated.
Place vegetables in a single layer on a large, rimmed baking sheet and lightly splash on balsamic vinegar to taste.
Bake at 400 F for 15 mins, toss vegetables or rotate the pan, then bake for another 10 minutes. Be careful not to overbake or the vegetables will release their water and become soggy.