01 -
Combine tuna, mayonnaise, Dijon mustard, garlic powder, onion powder, salt, and black pepper in a mixing bowl. Fold in diced jalapeños, shredded cheddar cheese, and green onions if using.
02 -
Butter one side of each bread slice. Place two slices butter-side down on a skillet heated over medium heat. Sprinkle shredded cheddar on one slice, spread tuna salad evenly over cheese, then top with the second slice of bread, buttered side up.
03 -
Cook sandwiches for 3-4 minutes per side, pressing gently with a spatula, until bread is golden brown and cheese is melted. Remove from heat and let rest for 1 minute before slicing.
04 -
Slice sandwiches in half and serve hot with preferred sides such as pickles, chips, or a fresh salad.