01 -
In a small saucepan, combine sugar and water. Bring to a gentle simmer over medium heat, stirring occasionally, until the sugar dissolves, about 2 minutes. Stir in lemon zest, remove from heat, and cover. Allow to steep for 5 minutes. Refrigerate, stirring occasionally, until thoroughly cooled, approximately 20 minutes.
02 -
Strain the cooled syrup through a fine-mesh sieve to remove the lemon zest. Discard the zest.
03 -
Combine the cooled lemon syrup, coconut milk, lemon juice, ice cubes, and frozen raspberries in a blender. Blend until the mixture is smooth and the ice is crushed into a slushy consistency, about 30 seconds.
04 -
Divide the whipped raspberry lemonade evenly among 4 glasses. Serve immediately.