Preheat oven to 400°F (200°C). Lightly butter nonstick muffin pans. In bowl, whisk together milk, yogurt, lemon rind and juice; let stand for 5 min. In separate large bowl, combine all-purpose and whole wheat flours, baking powder, baking soda, salt and a pinch of nutmeg. Whisk sugar, egg, butter and vanilla into milk mixture. Pour over dry ingredients and stir just until moistened. In bowl, whisk together milk, yogurt, lemon rind and juice; let stand for 5 min. In separate large bowl, combine all-purpose and whole wheat flours, baking powder, baking soda, salt and a pinch of nutmeg. Whisk sugar, egg, butter and vanilla into milk mixture. Pour over dry ingredients and stir just until moisten.
Spoon into prepared muffin pan and sprinkle a little nutmeg on top of each muffin. Bake for 20 to 25 minutes or until tops are firm to the touch. Let cool in pan for 10 min. Transfer to rack to cool completely.
