Help! I've been making macarons for years and have gotten down a lot of the process. However, no matter what I do my macarons ALWAYS have an air bubble in them. Sometimes it's large, sometimes it's small, and no matter what I change I can't figure out what's causing it. Does anyone have any idea what leads to air bubbles in macarons?! I'd post the recipe but I know this is a bit of a universal problem no matter what technique is used but will post if anyone thinks it will help troubleshoot.