This recipe is another one of my family's favorite sandwiches. Use your favorite cheese to make it perfect for you. You can either mix shredded cheese in with the tuna before you cook, lay sliced on top of the tuna before grilling on both sides, or toast the bread, then broil a piece of cheese on top for an open-faced sandwich. I found my favorite way to cook it is to use pumpernickel bread and grill it like grilled cheese. Once we burned our sandwiches by mistake, and we found that it made them taste that much better. Now we always burn them a little. Yum!