In medium bowl, combine flour, sugar, baking powder and salt; set aside. In small bowl, combine milk, sour cream and egg; stir into flour mixture with margarine until just blended. Gently stir in cookies. Spoon batter in to dozen grease 6 cm muffin-pan cups. Bake at 200ºC for 20 to 25 minutes or until toothpick inserted in center comes out clean. Remove from pan; cool on wire rack. Serve warm or cold. Makes 1 dozen muffins.