Zucchini, Summer Squash & Tomato Gratin

large onion sliced for caramelizing

Tbl. olive oil

garlic clove minced

sprigs fresh lemony thyme fine chopped

fresh basil leaves chopped

zucchini thin sliced

summer squash thin sliced

tomatoes thin sliced

grated Parmesan cheese

toasted bread crumbs (omit for gluten free)

olive oil to drizzle

sea salt & fresh cracked pepper