Cut yellow squash and zucchini into thin, ¼-inch slices.
Sprinkle salt over the zucchini and squash slices. Let sit for 10 minutes and then dab to remove excess moisture with a paper towel.
Spray a 9-inch square baking dish with non-stick cooking spray.
Alternatively, overlap the zucchini and squash in a row. Drizzle olive oil over the zucchini and squash and then sprinkle with salt and pepper.
In a small bowl combine Parmesan cheese, breadcrumbs, and garlic powder. Toss to combine and then sprinkle over the zucchini and squash.
Cover baking dish with aluminum foil and bake in preheated 350 degree oven for 25-30 minutes.
Remove foil and turn heat to a High broil. Broil for an additional 5-7 minutes, or until breadcrumb topping starts to turn a golden brown.
Serve immediately with fresh parsley and enjoy!