Tomatoes Stuffed with Tuna

Ingredients:

6 big tomatoes;
1 can solid white tuna in spring water,drained;
1/2 cup spring onion and fresh parsley leaves, chopped;
1 cup onion, chopped;
a trickle of extra virgin olive oil;
2 buffala mozzarella slices;
salt and fresh pepper.

Preparation:

Wash well the tomatoes and prepare them to stuffing: cut off a thin slice of the tomato´s top to make a support base. Cut around their stems with a small knife, then remove what is inside the tomatoes with the knife and a small spoon and put aside (you can use the inside´s flesh for the stuffing).
Place the tuna into a bowl, tear it a little, combine the other ingredients, taste the salt, and sprinkle a trickle oil.
Stuff the tomatoes by the mixture, top them with the mozzarella cheese, and place in oven until cheese is melted. Serve as hot dish.