In a small saucepan, combine honey, chili flakes, and cayenne pepper (if using).
Heat the mixture over medium heat until it comes to a simmer. Reduce heat to low and simmer for 5-10 minutes, stirring occasionally.
Once the mixture has infused with the chili flakes, remove it from the heat and let it cool for a few minutes. Stir in the apple cider vinegar.
Pour the hot honey through a fine mesh strainer to remove the chili flakes, if desired. Store in a clean jar or bottle and keep at room temperature.
