Preheat your oven to 400 degrees Fahrenheit (200 degrees Celsius). This temperature ensures that the sandwiches will be perfectly toasted and the cheese will melt evenly.
Step 2: Prepare the Tuna Salad
In a mixing bowl, combine the drained tuna, mayonnaise, sour cream, Dijon mustard, chopped celery, red onion, pickle relish, parsley, dill, and black pepper. Mix well until all the ingredients are thoroughly incorporated. This flavorful tuna salad will be the base of your Tuna Melt sandwiches.
Step 3: Toast the Bread
Lightly toast the slices of bread until they are just beginning to turn golden. This will provide a sturdy base for the tuna salad and prevent the bread from becoming soggy.
Step 4: Assemble the Sandwiches
Divide the tuna salad evenly between the toasted bread slices. Spread the mixture out evenly. Top each sandwich with two thin slices of tomato, then sprinkle the shredded cheddar cheese evenly over the tomatoes.
Step 5: Bake the Sandwiches
Place the assembled sandwiches on a baking sheet and bake in the preheated oven for 10-15 minutes, or until the cheese has melted and the sandwiches are warmed through. Serve promptly for the best texture and flavor.
