Spread pesto sauce evenly over two sliced ciabatta rolls. Layer sliced ham, tomatoes, mozzarella cheese, and Parmesan cheese between each roll. Grind freshly cracked pepper over each side. Melt butter in skillet, grill sandwich using a weight or press until golden browned. Turn over, adding additional butter to the pan and grill second side until golden browned and cheese has melted. If cheese doesn't melt completely, finish sandwich in 350 degree oven for 5-7 minutes.