Preheat oven 200°C fan forced. Lightly grease two pizza trays. Arrange the bread, buttered side up on the pizza trays.
Spread pizza sauce evenly over top of each bread slice. Top each pizza with green onions, ½ cup cheese, mushrooms, ham then remaining cheese.
Bake for 15 minutes, swapping the trays over after 10 minutes or until cheese is melted and bread is crisp. Serve.
Spoon bought basil pesto and finely grated parmesan over the pizza at the end step 3.