Slice the zucchini, squash, onion and tomato about 1/8-1/4 inch slices. Set aside.
Brush 1 tablespoon of oil into a 9 inch cast iron skillet or round pie dish. Layer the slices of vegetables in a spiral around the skillet.
Mix the remaining oil and garlic together then brush over the layers of vegetables. Sprinkle with herbs de provence, salt and pepper and bake for 40-45 minutes until the vegetbles look softened and are fork tender.
Sprinkle optional grated parmesan over the top once out of the oven before serving if desired. Store in the refrigerator for up to 5 days.