Ingredients:

  • 1/2 small red onion, thinly sliced
  • 1/4 cup apple cider vinegar
  • 1 tablespoon granulated sugar
  • 1/4 teaspoon salt
  • 2 (5-ounce) cans tuna in water, drained well
  • 1/4 cup mayonnaise
  • 1 tablespoon Dijon mustard
  • 1 tablespoon chopped fresh parsley
  • 1 tablespoon chopped celery
  • 1/4 teaspoon black pepper
  • Pinch of red pepper flakes (optional)
  • 4 slices sourdough bread
  • 4 ounces sharp cheddar cheese, shredded
  • 2 tablespoons butter, softened

Instructions:

  1. Prepare Pickled Onions: Combine red onion, vinegar, sugar, and salt in a small saucepan. Bring to a simmer over medium heat, stirring until sugar dissolves. Remove from heat and let cool slightly while you prepare the tuna salad.
  2. Make Tuna Salad: In a medium bowl, flake the drained tuna. Add mayonnaise, Dijon mustard, parsley, celery, pepper, and red pepper flakes (if using). Mix well to combine.
  3. Assemble Melts: Spread softened butter on one side of each slice of bread. Place two slices of bread, butter-side down, on a griddle or in a large skillet over medium heat.
  4. Top with Cheese and Tuna: Top each slice of bread with half of the shredded cheddar cheese, then half of the tuna salad, then half of the pickled red onions (drained), and finally the rest of the cheddar cheese.
  5. Top with remaining bread: Top with remaining bread slices, butter-side up.
  6. Grill Melts: Cook for 3-5 minutes per side, or until the bread is golden brown and the cheese is melted and bubbly. Press down gently with a spatula to ensure even browning.
  7. Serve Immediately: Cut in half and serve immediately.