1. Preheat oven to 350 degrees F.
2. To prepare muffins, lightly spoon flour into a dry measuring cup, level with a knife. Combine flour, sugar, baking powder and salt in a large bowl, stir well with whisk. Make a well in the center of the mixture.
3. Combine sour cream and the next 6 ingredients (through the egg white) in a small bowl; stir with a whisk until well combined. Add to flour mixture, stirring just until moist.
4. Spoon batter evenly into 10 muffin cups coated with cooking spray. Bake at 350 degrees for 25 minutes or until muffins spring back when touched lightly in center. Remove from pans immediately. Cool completely on a wire rack.
5. To prepare glaze, combine powdered sugar, 1/2 teaspoon rind, and 3 tablespoons juice in a small bowl. Stir with a whisk until smooth. Spread about 1 teaspoon glaze over each muffin; let stand 5 minutes or until set. Garnish with lemon rind if desired.
Calories 166 (19% from fat); Fat 3.5 g (sat 0.7g, mono 2.4g, poly 0.3g); Protein 2.9g; Carb 31.2g; Fiber 0.4g; Chol 22mg; Iron 0.7mg; Sodium 131.mg; Calc 53mg