|A meringue for lemon macarons. I can tell it's done because it holds a soft peak.|
I am always happy and willing to help readers troubleshoot why their macarons aren't turning out. I find that helping others is also beneficial to me since there are so many variables to consider when baking macarons and there's always more to learn.
One of the most frequently asked questions I get is, "Why are my macarons hollow?" There are three reasons I can think of — The shells could have rested for too long before baking, the oven temperature could have been too high or you could have overbeaten the meringue. It's usually the latter.
You want to beat the meringue just until it holds a soft peak. Remember not to overbeat the egg whites and not to beat them too quickly.
You want to whip the egg whites slowly starting on medium-low speed, gradually adding the granulated sugar in three or four parts, and then increasing the speed to medium and then medium-high.
Getting the meringue to soft peaks should take a good seven or so minutes but it's so worth the time. If egg whites are beaten too quickly, the protein structure won't be strong, resulting in hollows.
If you want to color the meringue, add gel coloring towards the end of mixing and finish whipping to soft peaks.