This big batch of jalapeño-spiced orange-lime juice keeps in the fridge for a couple of days. Pour it over ice and top it with seltzer for a refreshing alcohol-free pick-me-up, or stir a splash of rum into your serving for a cocktail.
- 2 small jalapeños, divided
- 12 oz. white rum (optional)
Juice limes and 6 oranges into a large pitcher. (You should have about ¾ cup lime juice and 1¼ cups orange juice.) Discard lime rinds and half of the orange rinds. Cut remaining orange rinds into quarters and place in a large saucepan.
Coarsely chop 1 jalapeño and add to orange rinds along with sugar and salt. Using a muddler or dowel-style rolling pin, muddle rinds until thoroughly smooshed and much of the sugar and salt is dissolved, about 3 minutes. Stir in 1 cup warm water and let sit at least 10 minutes and up to 1 hour.
Strain orange mixture through a fine-mesh sieve into pitcher with juice, gently pressing with a spoon to extract as much liquid as possible; discard solids. Thinly slice remaining orange and add to pitcher. Remove seeds from remaining jalapeño; thinly slice into rounds and add to pitcher.
To serve, pour 2 oz. juice mixture and 1 oz. rum, if using, into an ice-filled glass. Top off with club soda; stir to combine.
Do Ahead: Juice mixture can be made 2 days ahead. Cover and chill.