Spray four 6-ounce custard cups with nonstick coating; set aside. In a medium mixing bowl combine peaches, granulated sugar, miniature chocolate pieces, flour, and lemon juice. Toss to mix; set filling aside.
Unfold phyllo dough. Spray 1 phyllo sheet with nonstick coating. Keep remaining phyllo sheets covered with plastic wrap to keep them from drying out. Place another sheet of phyllo on top of the first sheet; spray with nonstick coating. Repeat twice. Cut stack in half lengthwise and then in half crosswise to form 4 rectangles.
Using one stack of phyllo, gently ease center of phyllo into bottom and up sides of 1 custard cup (phyllo will hang over edge). Spoon about 1/2 cup of the peach filling into center. Bring phyllo up over filling, pinching together to form a ruffled edge. Spray again with nonstick coating. Repeat with remaining phyllo and filling. Place custard cups in a 15x10x1-inch baking pan.
Bake in a 375 degree F oven for 20 minutes. Cool 5 minutes in custard cups on a wire rack. Remove from cups. Cool slightly or completely. Sift powdered sugar over pastry tops before serving. If desired, garnish with a few fresh raspberries and fresh peach slices. Makes 4 servings.