Blend 1 egg and 1/2 cup milk in medium bowl, using fork. Stir in muffin mix just until moistened. Fold drained blueberries into batter. Fill muffin cups about 1/2 full. Bake 15 to 20 minutes or until light golden brown. Cool 5 minutes; gently loosen and remove from pan. Makes 12 medium muffins.