Step 1

Cut watermelon into cubes and make sure to cut the rind off. (Weight out slightly over a pound of watermelon chunks.)

Step 2

Place watermelon chunks into the blender and puree until completely smooth, when no little chunks remain.

Step 3

Strain the watermelon puree through a fine mesh strainer. (Swirl the puree in the strainer with a spoon if it needs more help straining.)

Step 4

At this point, you can make the cocktails right away or store the watermelon juice in the refrigerator for later. **

Step 5

Take mint leaves off the stem and add them into the cocktail shaker. Squeeze lime juice into the shaker as well and add simple syrup.

Step 6

Use a muddler to gently press on mint leaves just a few times. (The point to to bruise and muddle the mint, not mash it into a pulp!)

Step 7

Pour in rum, watermelon juice, add a little ice, and shake it all together for a few seconds.

Step 8

Add crushed ice into four highball glasses, about half way full, and divide the mixture evenly among the glasses. (Remember to leave room for club soda.

Step 9

Add 2-3 oz of seltzer water to each glass, gently stir to combine and serve.

Step 10

Divide mint leaves among the 4 highball glasses. Add 3/4 oz. lime juice and 3/4 oz. simple syrup to each glass.

Step 11

Use a muddler to gently press on mint leaves just a few times. Repeat in each glass.

Step 12

Add 2 oz. of rum and 4 oz watermelon juice into each glass and stir.

Step 13

Add ice to each glass, top off with 2-3 oz of club soda and give each cocktail a gentle stir. Serve right away.