In the height of the summer, the nectarines are so sweet and juicy, they need very little to bring out their flavor. Here is an easy, rustic tart to bring out the best in nectarines.
To make the dough, place the flour, salt and sugar in a bowl, cut in the cold butter with a pastry cutter. When the mixture looks like breadcrumbs or oatmeal flakes, add the water and mix with the fingers of one hand to bring into a ball. Knead lightly to get the mixture to come together. Place in wax paper in the fridge to chill for at least 20 minutes.
To make the filling, in a large bowl mix the sugar with the cornstarch. Gently toss in the nectarines, sprinkle with the lemon juice and let sit for 5 minutes, tossing occasionally.
Roll out the dough on a lightly floured surface to about 12 inches around. Fold the dough in half then half again and place on an ungreased baking sheet, unfold to make a round.
Pour the fruit and the juices into the pastry and mound it in the middle. Gently fold up the edges around filling, leaving a 6-inch opening of exposed fruit in the center of the pie. Brush water on the pastry, sprinkle with the remaining sugar. Bake the pie on the lower rack of a preheated 375 degree oven for 35 to 45 minutes. Serve with sweetened whipped cream if desired.