Zucchini Potato Bake

lbs baby potatoes, thickly sliced

lbs zucchini, thickly sliced

lbs cauliflower, thickly sliced

egg, large

Greek yogurt, plain (I used 2%, do not use 0%)

cornstarch

large garlic cloves, crushed

dill, chopped

salt

black pepper, ground

any shredded cheese, divided (I used part-skim mozzarella)

Cooking spray (I use Misto)