FOR THE PASTRY
Butter (for the pan)
2 cups flour
Pinch of salt
12 tablespoons (1½ sticks) unsalted butter, cut into small pieces
Pinch of sugar
3 tablespoons sour cream
1 egg, lightly beaten
Flour (for sprinkling)
1. Have on hand a 9-by-13-inch baking dish or a 12-inch pizza pan. Butter the pan. In a food processor, combine the flour and salt. Pulse once or twice to sift them. Distribute the butter on top and pulse the mixture until it resembles sand with some large clumps.
2. Sprinkle the sugar on top of the flour mixture. Pulse twice to mix it in.
3. In a small bowl mix the sour cream and egg. Sprinkle it on the flour mixture and pulse just until the dough begins to form large clumps. It should not come together to form a ball.
4. Transfer the dough to a lightly floured counter. Knead it lightly to form it into a dough, then flatten it and shape it into a round or rectangle (depending upon the shape of your pan). Wrap in foil and refrigerate for 20 to 30 minutes.
5. Roll the pastry on a lightly floured counter until it is 2 inches larger than the pan. Lift the dough up onto the rolling pin and ease it into the pan. Tuck the pastry in around the edges to make a neat hem. Refrigerate the dough.
FOR THE FILLING
2 large russet potatoes, peeled and very thinly sliced
Olive oil (for sprinkling)
1 tablespoon chopped rosemary
Salt and pepper, to taste
1. Set the oven at 375 degrees.
2. Overlap the potatoes on the pastry and sprinkle them lightly with oil, rosemary, salt, and pepper.
3. Bake the pastry for 35 to 40 minutes or until it is golden brown and the potatoes are tender. Remove the tart from the oven and set it aside to cool slightly. Cut into 2-inch pieces to serve.