Cut the potatoes into cubes, boil for 5 minutes in salted water, and drain (you can also grate the raw potatoes - then you don't need to boil them). In a bowl, add the potatoes and the rest of the ingredients for the filling and mix. In another bowl, add the flour, olive oil, salt, and water, and kned until you have a smooth dough. Add more water or flour, if needed.
Once the dough is ready, keep a piece aside to cover the pie. Split the rest into three balls. Flour a surface, and roll each ball of dough into a pastry, taking care to flour often so the dough does not become sticky.
Grease a baking dish with olive oil, and place the first pastry sheet in it. Add a little olive oil and place another pastry sheet on top. Then add the filling and spread evenly. Then place the third pastry sheet on top.
Using the dough you set aside in the beginning, make shapes (braids, spirals, etc), to decorate the pie, if you wish. Brush the surface of the pie with olive oil and a little water, and bake for about 70 minutes at 180C in a preheated oven.