MAKES 3 TO 4 CUPS (540 TO 720G)
- 2 large red onions
- 1 tablespoon kosher salt
- 2 tablespoons sugar
- 1 1/2 cups (355ml) cider vinegar
Slice the onions very thinly and put them in a microwave-safe container. Add the salt and sugar. Combine the cider vinegar and 3/4 cup (175ml) water, then pour over the onions, making sure they’re submerged.
Microwave for 1 minute, then stir and microwave for 1 minute more. Continue microwaving and stirring until the liquid is hot and the onions begin to soften— it usually takes me 3 to 4 minutes total, but may depend on your microwave. Let cool, transfer to a jar, then refrigerate overnight. The onions will keep for up to 2 weeks.