Spread the diced onions over the zucchini and cover it with a layer of shredded mozzarella cheese. Pour the Bisquick batter on top of the vegetables. Bake the crustless quiche until the batter ...

Stir in the onion and 1/2 teaspoon of the salt ... and then pour the egg-cheese mixture over the vegetables. Place the quiche on a rimmed baking sheet and bake until the filling is browned ...