Thanks to Duncan at Syrup and Tang, and Helene Dujardin of Tartlette, I am now making batch after batch of perfect macarons. I found Helene’s recipe for (French method) Lemon Verbena macarons and after 2 years and 3 months struggling to make the perfect shell, I began using this version for every batch.
I read incessantly about macarons, searching the web for hours to find just the right thing that might help me produce taller feet and macarons that don’t have sunken tops. Finally, everything that was said regarding not over mixing during the macaronage stage (mixing the meringue with the almond flour/confectioner’s sugar) sunk in and I now stop short of what has always seemed to me to be the correct consistency. It shouldn't be runny.
While reading, I came across a curious reference to using a pizza stone. After finding the oven tutorial at Syrup and Tang, I discovered that my oven had its heating element at the top, and my macaron shells were not getting sufficient heat to thoroughly cook them on the bottom, resulting in wet macarons. I now have my old pizza stone on the bottom rack of the oven and bake my macarons on the middle rack at 300 degrees for 18 minutes, rotating the pan at the 9 minute mark.
Another change has been that I no longer use 2 pans stacked inside one another, as my macarons don’t get enough heat as it is. They are baked on parchment paper on one baking sheet and have perfect feet every time, feet that do not deflate after being removed from the oven.
Best of luck!