1 (750-milliliter) bottle rosé wine (preferably something on the darker, bolder side)
1 pound watermelon cubes
1/2 cup granulated sugar
1/2 cup water
8 to 10 fresh mint leaves, plus more for garnish
1/4 cup freshly squeezed lemon juice
Pour the rosé into ice cube trays and freeze for at least 6 hours or preferably overnight. Place the watermelon on a baking sheet lined with parchment paper so that the cubes are not touching each other. Freeze for at least 2 hours, then transfer the watermelon into a container or zip-top bag and keep frozen.
Make the mint simple syrup: Combine the sugar and water in a small saucepan over medium heat, stirring constantly until dissolved. Add the mint and bring to a boil. Once boiling, turn off the heat and let sit for 15 minutes. Strain the syrup into a small bowl, discard the mint leaves, and let the syrup cool before putting it into the refrigerator until ready to make the drink.
Place the rosé ice cubes, frozen watermelon, mint simple syrup, and lemon juice in a blender and blend until combined and creamy. Pour into glasses and garnish each glass with a sprig of mint.