Watermelon Gin Fizz: 5 cups diced watermelon (divided), 6 oz gin (divided), 8 tablespoons lime juice (divided), 1.33 cups ginger ale (divided), Lime wedges for garnish. Freeze 1 cup watermelon for garnish. Puree the remaining 4 cups watermelon. Strain; divide the juice among 4 ice-filled glasses. Top each with 1 1/2 ounces gin, 2 tablespoons lime juice, and 1/3 cup ginger ale. Garnish with the frozen watermelon and lime wedges. Nonalcoholic variation: Omit the gin.