Flaky Pie Dough: Combine flour, salt and baking powder in work bowl of food processor and pulse 2 to 3 times to mix. Cut butter into 8 pieces and add to bowl. Pulse rapidly about 15 times, until mixture resembles coarse cornmeal and no large pieces of butter remain visable. Add 2 tablespoons water and pulse 4 or 5 times to mix checking to see if most, but not all, of dough forms a ball. If dough remains dry, add remaining 1 tablespoon water, sprinkling it on dough and pulsing again 4 or 5 times. Remove dough from processor and quickly form into ball with floured hands. Place dough on piece of lightly floured plastic wrap. Lightly flour top of dough and cover top with plastic wrap. Press with palm of hand to form dough into a 6-inch diameter disk. Refrigerate dough while preparing topping. Crumb Topping: Combine brown sugar and flour in mixing bowl. Add butter and stir in evenly. Set mixture aside 5 minutes. Then, using fingertips, break mixture into 1/4- to 1/2-inch crumbs. Set aside. Dough Preparation: Remove dough from refrigerator and place on flat work surface. Roll dough, still between sheets of plastic, to 12-inch disk. Peel off top plastic and ease dough into 9-inch pie pan. Gently press dough into pan and peel off top plastic. Trim excess dough to within 1/2-inch of pan edge, turning excess dough under around edges; flute edges. Chill pie shell while preparing Filling. Filling: Peel, halve and core apples; cut into 1/2-inch pieces. Place apples in bowl with sugar, flour, cinnamon and lemon zest, tossing well to combine. Place filling in dough-lined pan, mounding it slightly in center. Dot filling with butter and cover with reserved Crumb Topping. Bake pie on bottom rack 15 minutes at 400 degrees. Lower temperature to 350 degrees and move pie to middle rack. Bake 20 to 30 minutes longer, until crust edges are deep golden brown and juices just begin to bubble up. Cool pie on rack and serve warm or at room temperature. Makes 8 servings.