More delicious than pizza

Ingredients:

bread (400g).
~ 1/4 cup butter (80g).
1 small onion.
1 can of corn (75g).
2 cans of tuna (160g).
1 tomato.
3 eggs.
a pinch of salt.
a pinch of black pepper.
parsley.
200 grams of grated mozzarella cheese.
oregano or thyme.