Ingredient:

• 1 medium red onion, very thinly sliced
• ½ cup water
• ¼ cup distilled white vinegar
• ¼ cup apple cider vinegar or additional white vinegar
• 1 ½ tablespoons maple syrup or honey
• 1 ½ teaspoons fine sea salt
• ¼ teaspoon red pepper flakes (optional, for heat)