How to Make It
In a small pan, heat the milk to lukewarm. In a bowl, mix together the flour, sugar, baking powder and salt. Add the shortening and mix with a spoon or with your hands until the mixture feels and looks sandy. Add the warm milk and mix rapidly until the dough forms a ball.
Roll the dough between 2 sheets of plastic wrap to an 11- to 12-inch round. Remove the top piece of plastic and, using the bottom piece, invert the dough into a 9-inch tart pan with a removable bottom; peel off the remaining plastic.
Preheat the oven to 400°. Peel, quarter and core the apples. Cut them into 1-inch-thick wedges. Arrange the apple wedges in a concentric circle on the dough and sprinkle evenly with the sugar and butter.
Set the tart on a baking sheet and bake for about 1 hour, or until the apples are tender and the pastry is golden. Cover the tart loosely with foil after 45 minutes to prevent over-browning. Cut the tart into wedges and serve warm.