Preheat the oven to 400 degrees.
To make the filling, in a large saucepan heat 1 tablespoon of the oil over medium heat. Add the onion and garlic and cook, stirring, for 5 minutes. Add the water, parsley, potatoes, carrots, parsley, salt, and pepper, and bring to a simmer. Cook over medium-low heat, stirring occasionally, until the vegetables are tender, about 20 to 25 minutes. Stir in the peas and cook for 5 minutes more. To thicken, mash the potatoes and parsnips against the side of the pan with the back of a spoon. Remove from the heat and let cool slightly.
To make the crust, in a large mixing bowl combine the flour and salt. Blend in 1-1/2 cups of the oil and water and form a large moist ball of dough. Divide dough into four balls of equal size. On a lightly floured, flat surface, roll out the balls of dough into 1/8-inch-thick rounds about 10 inches in diameter. Place two of the rounds into the bottom of two lightly greased 9-inch-round deep-dish pie pans. Bake for 5 to 7 minutes; cool for about 5 minutes.
Pour the filling equally into the pie pans. Cover the filling with the two remaining round crusts, and crimp the edges with a fork. Pierce the tops with a fork two or three times. Bake until the tops are lightly browned, about 20 to 25 minutes. Cool for 10 minutes before serving.