Preheat the oven to 400 degrees. Coat a small baking dish with cooking spray.
Place the sliced zucchini and squash coins into a bowl, then season with a bit of olive oil, sea salt, and freshly cracked pepper, to taste; toss to coat evenly.
In another bowl, add the green onions, garlic, fresh basil, and feta cheese and mix well.
Lay the zucchini slices in the pan, slightly overlapping them like shingles. Sprinkle with some of the feta mixture.
Layer the yellow squash slices on top of the zucchini, slightly overlapping them like shingles. Sprinkle with some of the feta mixture.
Layer the tomatoes on top of the yellow squash, slightly overlapping them like shingles. Sprinkle with the remaining feta mixture.
Drizzle with some additional olive oil if desired.
Put in the oven and bake for 30 minutes or until the vegetables are tender and the top is slightly browned.
Allow it to sit for 5-10 minutes before serving. Enjoy.