From the story An East Bay Winter Whiskey Ramble by Serena Bartlett
I learned about this combination from the restaurant manager at Oakland’s di Bartolo, a knowledgeable chap with many innovative drink ideas up his sleeve. You may need to wait until next summer to make it, but some of us planned ahead and cut up a locally grown watermelon into cubes and tucked them into the freezer.
4 cups frozen watermelon cubes
1 bunch fresh spearmint
Juice of one lime
½ cup simple syrup
Place the frozen watermelon cubes in a mixing bowl and use a hand blender to mix until textured but smooth. Stir in simple syrup and blend. Muddle the mint in each glass and sprinkle with lime juice. Fill each glass with the watermelon mixture and leave room for a healthy float of whiskey.