Add in zucchini. Cook approx 15 minutes or until zucchini is tender.
Using a colander, drain water off of zucchini
Using a small scoop, scoop out the zucchini flesh to make a boat shape.
In a medium sized mixing bowl, add the zucchini flesh, cheddar cheese, bread crumbs, parsley, onion, salt, egg, and the parmesan cheese (reserve a little of the cheese for later). Stir to mix well.
Spoon the zucchini mix into the scooped out zucchini boats.
Arrange the filled zucchini in a baking dish
Placed diced butter on top of the filled zucchini.
Sprinkle the rest of the parmesan cheese on top of the zucchini