The leek is the national symbol of Wales, although it is native to the eastern Mediterranean and was probably taken to the British Isles by the Romans. Its delicate flavor—milder and sweeter than onions or garlic—combines perfectly with the potatoes and goat cheese in this recipe.
To prepare the crust, combine the flour and salt in a mixing bowl. Add the shortening and incorporate with your fingertips until the mixture resembles very coarse cornmeal. Sprinkle 3 to 4 tablespoons of the water over the flour mixture in 1-tablespoon increments while stirring with a fork. Add more water if needed. Form the dough into a ball, wrap in wax paper or plastic, and let rest for 1 hour in the refrigerator.
Preheat the oven to 425 F.
On a lightly floured work surface, roll out the dough into an 11-inch circle with a 1/8-inch thickness. Place the dough into an 8-inch pie pan, trimming and crimping the edges. Place the pie shell in the freezer for 20 minutes.
To prepare the filling, combine the stock and cream in a saucepan and bring to a simmer. Remove from the heat and whisk in the goat cheese until the mixture is smooth. In a mixing bowl, combine the leeks, garlic puree, and potatoes. Add the goat cheese mixture and salt and toss until thoroughly combined. Remove the pie shell from the freezer, fill with the mixture, and bake in the oven for 45 minutes, or until the potatoes are tender and the top is golden brown. Serve hot.