1. Preheat oven to 425°F. In bowl, stir baking mix and 1 tablespoon sugar. With pastry blender or 2 knives used scissors fashion, cut butter or margarine into baking mix until mixture resembles coarse crumbs. Add milk, mixing lightly with fork until dough just holds together. Divide dough in half; shape into two 3-inch rounds. Place on ungreased cookie sheet. Bake 10 to 12 minutes until lightly browned; cool slightly.
2. In small bowl, mix sour cream, orange-flavor liqueur, and 1 tablespoon sugar. Split warm biscuits horizontally in half; arrange bottom halves on 2 dessert plates.
3. Spoon half of sour-cream mixture on biscuits; top with some peach-pie filling (use leftover filling as ice-cream sauce another day); replace tops of biscuits. Garnish shortcakes with remaining sour-cream mixture.