Ingredient:

• ⅓ medium watermelon, preferably chilled (seedless watermelon is the easiest to work with, but sugar baby watermelons are the most tasty)
• 1 bottle Champagne, chilled (I like brut Champagne, but if you like sweeter Champagne, that works, too)
• Optional, for extra sweetness: simple syrup or St. Germain, to taste