Ingredients:
- 1 large red onion, thinly sliced
- 1 1/4 cups rice wine vinegar or white wine vinegar
- 1/2 cup water
- 3 tablespoons granulated sugar
- 1 tablespoon kosher salt
- Pinch of crushed red pepper flakes (optional)
Directions:
- Add sliced onions to a container with a tight lid, such as a mason jar.
- Add the next 4 ingredients to a small pot over medium high heat. Bring to a boil, making sure that the salt and sugar dissolve completely.
- Remove from heat, and pour over onions. Add crushed red pepper flakes to mixture, if desired.
- Allow onion mixture to cool to room temperature; cover with lid and refrigerate for at least 2 hours before using.