1/2 cup apple-cider vinegar
2/3 cup packed light-brown sugar
1 teaspoon salt
1/2 teaspoon ground cardamom
1 cup candied orange peel, cut into 1/4 inch pieces
1/2 cup finely diced celery, (2 to 3 ribs)
1 1/2 cups finely diced red onion, (1 medium red onion)
2 apples, peeled, cored, and cut into 1/4 inch cubes
5 cups whole frozen cranberries
Combine vinegar, sugar, salt, cardamom, orange peel, celery, onion, apples, and 2 cups water in a low-sided, 6-quart saucepan.
Set over medium-high heat; bring to a boil.
Reduce heat to a simmer, and cook until apples are tender and most of the liquid has been absorbed, 30 to 40 minutes.
Stir in cranberries; cook until they begin to pop, 10 to 15 minutes.
Remove pan from heat.
Transfer to a large bowl set over an ice bath to chill; store in an airtight container, refrigerated, up to 4 weeks.