Barefoot Contessa (en-US)

2 (6 to 8-ounce) jars imported tuna packed in olive oil, drained
½ cup (¼-inch) diced hearts of celery
½ cup minced scallions, white and light green parts (3 scallions)
3 tablespoons minced fresh dill
2 tablespoons freshly squeezed lemon juice
Kosher salt and freshly ground black pepper
¾ cup good mayonnaise, such as Hellmann’s
1 teaspoon anchovy paste (optional)
4 large slices bread, such as Pepperidge Farm Farmhouse Hearty White
4 ounces Swiss cheese, such as Emmentaler, grated
1 ounce microgreens

In a medium bowl, flake the tuna finely with a fork. Add the celery, scallions, and dill, and continue mixing and fluffing with the fork until combined. Add the lemon juice, 1½ teaspoons salt, and ¾ teaspoon pepper. Combine the mayonnaise and anchovy paste, if using, and mix into the tuna.

Preheat the broiler. Toast the bread in a toaster and place the slices in a single layer on a sheet pan. Spread a quarter of the tuna mixture thickly and evenly on each piece of bread, covering the entire slice. Sprinkle the cheese evenly on the 4 sandwiches, covering the tuna completely. Broil for 1 to 2 minutes, just until the cheese melts and starts to brown. (Watch it carefully!) Sprinkle with the microgreens and serve hot.

Ultimate Tuna Melts