Preheat oven to 375. Slice the garlic and onion. Saute over medium high in a skillet with olive oil for 5-8 minutes, until the onions are translucent.
Add the tomato sauce to the skillet and reduce to a simmer.
Finely slice all of the vegetables using a mandoline to roughly 1/16 of an inch.
Pour the warm tomato sauce mixture into the bottom of your prepared dish.
Arrange the vegetables into a pattern on top of the sauce. (This is where your kids can get creatively involved!)
Top the veggies with fresh parmesan, salt and pepper.
Bake at 375 for 45 minutes, until the tomato sauce is bubbling and the veggies are tender.