1 can (7 oz) tuna in oil
8.5 oz (240 g) flour
4.5 oz (125 fl oz) dry white wine
23 oz (600 g) red or yellow onion
3 tbsp vegetable oil
3 tbsp capers
1 tsp salt
1 tsp sugar
1/2 tsp ground black pepper
Blend a flour, an oil, a wine, and a ½ tsp salt together, until a dough became non-sticky.
Roll the dough in a piece of a plastic wrap, and let to sit in a room temperature for about 30 minutes.
Meanwhile, peel onions, and cut them alongside into medium pieces.
Pre-heat a wide skillet, pour 2 tbsp oil into skillet, let to boil, and put the onions.
Cover the skillet with a lid, and cook for 15-20 minutes with a small heating.
Then, add a salt, a sugar, and a ground black pepper, stir well, and increase the heating to medium one.
Stir-fry, until all juices evaporate, and onions get a light-brown color.
Turn the heating off.
Add a tuna with oil and capers into the skillet, press the tuna to get small pieces, stir well, and let to chill.
Pre-heat an oven to 350 F (175 C).
Divide the dough into 2 equal parts.
Sprinkle a table with the flour.
Roll out both pieces of dough thinly, into a shape of a baking dish (dough has to cover bottom and sides of the dish).
Put one piece of dough into baking dish, to cover bottom and sides of dish, and pierce dough some times using a fork.
Put a stuffing from skillet on top, smoothed, and cover with the other piece of dough.
Pinch dough's edges.
Bake for 20 minutes.
Then, spread the pie top with 1 tbsp vegetable oil, and bake for 15 more minutes.
Take pie out, let to chill, slice into portions, and serve.