Combine first 3 ingredients in a large bowl. Add margarine, 1/4 cup sugar, egg substitute, and vanilla; stir until well blended (mixture will be stiff). Knead lightly until smooth. Shape dough into a ball; wrap in wax paper, and chill 1 hour.
Shape dough into 1-inch balls; roll each into a log, and shape into a crescent. Place on baking sheets coated with cooking spray. Bake at 325° for 10 to 15 minutes. Remove to wire racks to cool slightly; sprinkle cookies with remaining 1 tablespoon plus 1 teaspoon powdered sugar, and cool completely on wire racks.