Combine the apples, raisins, brown sugar, cinnamon, and nutmeg in a baking dish. Bake until the fruit is tender, about 15 to 20 minutes. Remove from the oven and allow the mixture to cool. Increase the oven temperature to 450 degrees F.
Lay the 3 sheets of phyllo in a stack on a large nonstick baking sheet. Mound the fruit mixture in a row running along 1 of the short sides of the phyllo, leaving about 1 1/2 inches empty around the apples on the sides. Fold the close short side over the apples and fold in the long sides. Roll the phyllo and filling over onto itself to form a strudel roll. Place the roll seam side on the baking sheet. Brush the top of the strudel with the butter. Score the strudel with a sharp knife to mark the 6 portions.
Bake to a golden brown, about 10 to 15 minutes. Allow to cool for 10 minutes, then cut into portions. Decorate 6 dessert plates with the berry sauce and top with the pieces of strudel. Dust with a sifting of the confectioners' sugar, if using, and serve.
Fresh Berry Sauce:
Combine all the ingredients in a blender. Puree until smooth. Push through a fine sieve to remove the seeds. Use as directed.
Recipe courtesy Paul Ramsey, Frances Towner Giedt and Bonnie Sanders Polin, Ph.D, "The Joslin Diabetes Great Chefs Cook Healthy Cookbook", Simon and Schuster, 2002