1. Preheat oven to 180°. In a medium bowl, whisk together flour, sugar, baking powder and salt. In a small bowl, combine sour cream, grated lemon zest, olive oil, milk, lemon juice, large egg and egg white. Pour wet mixture into the bowl with the dry mixture slowly, stirring just until moist.
2. Spoon batter evenly into 12 muffin cups coated with Bertolli Light in Taste olive oil spray. Bake for 20-25 minutes or until muffins spring back when touched lightly in centre. Remove from pan immediately.
3. To prepare glaze, combine powdered sugar, lemon rind, and lemon juice in a small bowl; stir with a whisk until smooth. While muffins are still warm, spread about 1 teaspoon glaze over each muffin; let stand 5 minutes or until set. Garnish with lemon rind.