ULTIMATE TUNA MELTOne of the best sandwiches I’ve ever made - the Ultimate Tuna Melt! This sandwich has it all: Creamy tuna with a bit of sweetness and crunch from the apple, plenty of melted cheese, all topped with a delicious combination of avocado, mango, and pepperoncini. I used smoked tuna, but you could definitely try it with baked, grilled, or even canned tuna.