For the Basil Syrup: In a small saucepan, bring the water and sugar to a simmer. Stir until sugar dissolves. Add basil and cool to room temperature. Strain and keep in an airtight container in the refrigerator up to 1 month.
For the Pink Rim: On a plate, mix together salt and sugar. Rub the rims of the glasses with extra watermelon or lime and dip in the pink rim mixture. Set glasses aside.
For the Smash: In a pitcher with ice, add the watermelon juice, lime juice, basil simple syrup, tequila, and POM Juice and stir. Pour into glasses filled with ice, top with club soda and serve garnished with watermelon and fresh basil.
Tip: For a mocktail version, simply omit the tequila.
Basil Simple Syrup:
1 cup sugar
1 cup water
1 cup packed fresh basil leaves, plus more for garnish
Himalayan pink salt
¾ cup watermelon juice, blended and strained
¼ cup fresh lime juice
2 tablespoons basil simple syrup
½ cup silver tequila
6 tablespoons POM Wonderful 100% Pomegranate Juice