Prepare all ingredients.
Dice zucchini in one inch in size rings. Brown both sides on a grill or your oven broiler. Place zucchini on the bottom of a baking dish, I proffered one layer but it's up to you.
Dice mushrooms and cook on a skillet, season with salt. Cook until they are golden brown.
Top zucchini with sauteed mushrooms, set aside.
In a large skillet, preheat whipping cream, season it with garlic salt, add parmesan cheese and press garlic into it.
Pour the sauce over zucchini. Top the sauce with grated mozzarella cheese. Bake it at 350F for about 15 minute or until top is golden brown.
Serve this dish while it's hot, while the cheese is still melted.