Set aside.Using a mandolin slicer, slice the zucchini into as many thin slices as possible and set aside.Add the ricotta, Parmesan, garlic cloves, salt, pepper, and egg to a processor and blend until fully combined.In a oven safe skillet or casserole dish first make a layer of the ground beef.Make two layers of the zucchini criss crossing.Add a generous layer of the ricotta mixture.Sprinkle on some of the shredded mozzarella.Repeat this a second time (we made two full layers in our 6 inch skillet).