Source: bonappetit.com, August 2016

Ingredients

2 cups unseasoned rice vinegar
½ cup sugar
3 tablespoons kosher salt
4 Hungarian wax peppers
6 Italian frying peppers
4 jalapeños, sliced into rings

Directions

Whisk vinegar, sugar, salt, and 1½ cups water in a large glass jar until sugar dissolves. Prick Hungarian wax peppers and Italian frying peppers all over with a cake tester or the point of a sharp paring knife (this helps the brine penetrate the chiles faster). Add both peppers and jalapeños to jar and chill at least 12 hours before using.

Do Ahead: Chiles can be pickled 2 weeks ahead. Keep chilled.