Slice the Zucchini into thick rounds. Combine the melted butter and crushed garlic in a small bowl. set aside.
When the coals on your barbeque are almost burned down, lay your zucchini slices on the grill. Let cook for three minutes then turn over and brush the butter/garlic mixture on each slice. Cook for three more minutes and turn over again and brush the other side with the garlic and butter.
Cover the slices with pizza sauce and cheese and let cook until the cheese begins to melt.