What can I make that is cold and based on black lilac syrup?

If you're looking for a cold cocktail using black lilac syrup, you might consider trying something along the lines of the "Purple Lagoon" cocktail. While the actual provided cocktail recipes don't feature black lilac syrup specifically, the "Purple Lagoon" offers a similar aesthetic with its beautiful purple hue and refreshing taste. It combines the crispness of vodka with tangy lemonade, sweet grenadine, and a hint of orange liqueur from the Blue Curaçao, stirred to perfection and served in a highball glass.

Although the exact ingredients differ, you could easily modify this recipe to include black lilac syrup in place of one of the sweet components like grenadine or Blue Curaçao, keeping the overall flavor balance intact. The vibrant color and the blend of sweet and tangy notes make it a delightful choice that will appeal to those looking for a visually striking and refreshing drink. Additionally, the refreshing qualities of lemonade mixed with the subtle flavors of black lilac syrup would make this a perfect cocktail for a warm summer day.