Preheat oven to 350 degrees. Line a 12-cup muffin pan with paper liners, and then spray the liners with cooking spray.
- In small bowl whisk together 1½ cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon baking soda and ¼ teaspoon salt. Set aside.
- In a larger bowl place 2 Tbsp. soft tub margarine, 2 Tbsp. canola oil and ½ cup sugar substitute such as Splenda sucralose. Beat with electric mixer until crumbly. Beat in 1 large egg, 2 teaspoons grated lemon peel and 1 teaspoon vanilla extract.
- Add the flour mixture and 1¼ cups plain low-fat yogurt, alternately to the sugar substitute mixture, beginning and ending with flour mixture. Beat well after each addition. Stir in 1 cup fresh blueberries.
- Spoon the batter evenly into the 12 muffin cups. Bake for 20-30 minutes or until a wooden toothpick inserted in the centers comes out clean and cupcakes are lightly browned. Cool in pan for 5 minutes before removing the cupcakes to a wire rack to cool completely.
- Cut up 4 ounces reduced-fat cream cheese into cubes and place into mixing bowl. Beat with electric mixer until smooth.
- Add 1 teaspoon vanilla extract, ½ cup powdered sugar and ¼ cup sugar substitute such as Splenda. Beat at low speed until blended; increase to high speed and beat just until smooth.
- Refrigerate for 15-30 minutes before spreading evenly on the cupcakes.