Preheat oven to 400°. Grease 12-cup muffin pan or line with paper cupcake liners; set aside.
Combine flour, baking powder and salt in medium bowl; set aside.
Toss blueberries with 1 tablespoon flour mixture in small bowl; set aside.
Beat margarine with Splenda in large bowl until smooth. Beat in eggs and vanilla until blended, scraping sides occasionally. Alternately beat in flour mixture and milk just until blended, beginning and ending with flour mixture. Gently fold in blueberries. Evenly spoon batter into prepared pan.
Bake 23 minutes or until toothpick inserted in centers comes out clean. Cool 10 minutes on wire rack; remove from pan and cool completely.
