Lightly toast the slices of bread in a toaster, then place them in a baking tray or baking pan that's lined with foil paper, all in a single layer

Drain the cans of tuna into a fine sieve with a bowl underneath, gently flake the tuna, then add into a large bowl, along with the mayonnaise, dijon mustard, shallot, garlic, paprika, lemon juice and parsley, season with sea salt & black pepper, mix together until well mixed

Evenly spread the tuna mixture over the 4 slices of toasted bread

Thinly slice the tomato, add a couple of slices over each bread, then top off with the shredded cheese, making sure to cover the entire surface

Add into a preheated oven, broil only option (top heat), between 4 to 5 minutes or until the cheese is fully melted, then remove from the oven

Sprinkle each one with chopped fresh parsley, serve at once, enjoy!