Step 1

To prepare simple syrup: Bring sugar and water to a simmer in a small saucepan over medium heat, stirring occasionally until the sugar dissolves. Stir in lemon zest and remove from heat. Cover and let steep for 1 hour, then strain the syrup through a fine-mesh sieve; discard the zest. (You'll have extra syrup; refrigerate for up to 1 week.)

Step 2

To prepare whipped lemonade: Add 1/2 cup simple syrup, lemon juice, coconut milk and ice to a blender. Blend until the ice is crushed and the mixture is slushy. Divide between 4 8-ounce glasses and serve immediately.