Step 1 – Wash the tomatoes and remove the tops with a knife. Carefully remove the insides of the tomato with a spoon. Place the tomatoes face down so that all of the juices drain out, then set aside.
Step 2 – Separately, open a can of tuna fish and drain. Crumble the tuna in a bowl. Add the green onion and parsley and season with salt, lemon juice and oil, then mix well.
Step 3 – Fill the reserved tomatoes completely with the tuna mixture.
Step 4 – Place on top of lettuce slices on a plate with hardboiled egg, olives and mayonnaise.
Step 5 – Optional: Cut up the tomato pulp and add to the tuna mixture for the filling.