1 To Make the Pastry: In the bowl of a food processor, blend together flour and salt. Add the butter and pulse until butter is coated with flour. With the processor running, add the egg yolk and 1 to 4 tablespoons ice water, until the dough forms a ball. Remove, wrap in plastic and refrigerate at least 30 minutes.
2 To Make the Filling: In a large skillet over medium heat, melt the butter. Add leeks, salt and pepper to taste, and 1 tablespoon water. Wilt, stirring frequently, for 6 minutes. If leeks are getting too dry, add more water, 1 tablespoon at a time.
3 Add cream, 1/4 cup at a time, while stirring constantly, and allow most of it to absorb before adding another 1/4 cup until all the cream has been used.
4 Cut the potatoes in half lengthwise and then into 1/2-inch slices. Add dill and potato slices to leeks and mix thoroughly. Remove from heat.
5 Heat oven to 350 degrees. Remove pastry from refrigerator and, on a lightly floured surface, roll to a 17-inch circle. If making a free-form tart, place the circle on a parchment-lined baking sheet. If using a 15-inch springform pan, place the pan on a baking sheet, fit the dough into the pan, and fold down the sides to form a thick wall.
4 For the free-form tart, spread the filling on the circle to within 2 1/2-inches all the way around. Fold the border back up over the filling (as for Rustic Strawberry-Rhubarb Tart). If using a springform pan, spread the filling evenly in the crust.
5 Sprinkle grated cheese over top of tart, and bake about 40 minutes until bubbly and crust is well browned. Eat warm or at room temperature. |