Tuna Melt Sub

Finely dice the red onion. Place the diced onion in a bowl and cover with cold water to soak. Let it sit while you prepare the other ingredients.

Using a vegetable peeler, peel the outer membrane from the celery stalks, then finely dice the celery.

In a large mixing bowl, combine the drained tuna, the soaked and drained red onion, diced celery, and chopped fresh parsley.

Add the pickle relish, horseradish mustard, and buffalo sauce to the bowl.

Add the mayonnaise, paprika, garlic powder, salt, pepper, and sazón seasoning.

Mix all ingredients thoroughly until well combined.

Slice the hoagie roll open lengthwise, but not all the way through. Lightly spray the inside with cooking oil.

Toast the roll under a broiler or in a toaster oven until lightly golden.

Lay the Swiss cheese slices on the toasted roll and return to the broiler to melt.

Once the Swiss cheese is melted, spread the tuna salad mixture evenly over the cheese.

Top the tuna salad with the shredded Gouda cheese.

Return the sub to the broiler one last time to melt the Gouda cheese until bubbly and golden.

Close the sandwich, slice if desired, and serve immediately.