My top tips for macaroon success are: For best results use an electric mixer. You will also need a sugar thermometer for this recipe. Aging the egg whites dehydrates them, resulting in a firmer, more stable meringue. After separating your eggs, I recommend leaving the whites in a sealed bowl in the fridge for up to three days. Just be sure to bring them back to room temperature before using.
Flower essences can be overpowering if you are not careful, so pay attention to quality and quantity and use alight hand to dispense them! Finally check the weather forecast! Macaroons need a fine day. If it's wet or extremely humid, your macaroons will not dry properly and the shells will crack in the oven.