Preheat your oven to 350°F. Lightly grill or broil the zucchini rounds until they are tender and slightly browned on both sides. Arrange them in a single layer at the bottom of a baking dish.
Heat a skillet over medium heat, add olive oil, and sauté the diced mushrooms until they are golden and cooked through. Season with salt, then spread the mushrooms evenly over the zucchini.
Pour the alfredo sauce evenly over the zucchini and mushrooms, making sure everything is well-coated. Sprinkle the shredded mozzarella cheese on top.
Bake the dish in the preheated oven for approximately 15 minutes, or until the cheese is melted, bubbly, and lightly browned on top.
Serve immediately, enjoying the gooey, melted cheese while it's hot.