For dough, in a medium bowl stir together the flour, 1/2 cup sugar, and the baking powder. Using a pastry blender, cut in butter until mixture resembles coarse crumbs. Combine egg and 1 tablespoon of the milk; add to flour mixture, stirring to moisten. Add enough of remaining milk to moisten all the flour.
Turn dough out onto a lightly floured surface. Gently knead 10 to 12 strokes or until nearly smooth. (Dough will be soft.) Roll dough to a 14x7-1/2-inch rectangle; cut lengthwise into ten 3/4-inch-wide strips. Cut five of the strips in half crosswise. (You will have ten short strips and five long strips.) Cover with plastic wrap; set aside. Preheat oven to 350 degree F.
For filling, in a Dutch oven combine 1/2 cup sugar, nuts, raisins, cinnamon, and nutmeg. Stir in peaches and nectarines. Cook over medium heat about 5 minutes or until bubbly, stirring occasionally.
Spoon fruit filling into a 3-quart rectangular baking dish. Gently place dough strips over filling in a mock-lattice pattern, trimming ends as necessary. Short dough strips wont reach completely across dish, but spread as they bake. Sprinkle with 1 tablespoon sugar. Place dish on a baking sheet. Bake for 35 to 40 minutes or until top is golden brown. Serve warm. Makes 12 servings.