Combine ice, lemonade mix, water and 1 oz. of grape syrup in a blender. Blend until smooth. Pour into a chilled glass. Set aside.
Whip milk with a handheld frother for 20-30 seconds or until thickened. Add remaining grape syrup and whip mixture an additional 10 seconds to incorporate the syrup into the whipped oat milk.
Spoon or pour mixture on top of the refresher and garnish with a lemon slice if desired. Serve.
