Why are my macarons cracking on top?

I suspect high humidity or overbeating.

If they are not getting dull and dry, they are not ready to go in the oven. If you touch it and it wiggles around a bit, leave it to dry longer. It sounds like humidity shouldn't be a problem, as you have already tried letting them dry out longer, but if it is, here are some ideas.

Allow the macarons to dry for longer.

Heat up the oven to dry out to the room or use a hair dryer to dry the macarons.

Or turn on the heater or air conditioner to dry out the room.

The top of the macarons should be very dry to the touch prior to baking.

Add 2tsp corn starch or potato starch to the batter if it is humid in your area. This will add some extra tackiness to your batter and should dry out your macarons.

Another issue could be the temperature is too high when baking in humidity.

Lower oven temperature when higher humidity levels.

In dry weather, I bake for 11 minutes at 350.

In medium humidity, I bake for 12 minutes at 325.

In wet weather, I bake for 13 minutes as 305 degrees.

99.9% of the time, cracks are because you did not dry the macaroons out long enough. The 0.01% is that you overmixed or undermixed the batter.

You had too much air in your batter. This isn't a result of beating to much, but rather insufficient macaronage after folding in the sugar and almonds. The excess air expands in the oven and creates a hollow shell that then collapses.

The macaronage is really the trickiest thing about macarons - it is very hard to convey in recipes exactly what the texture of the batter should be after the process. It just takes practice and experience. It is hard to get out of the sponge-making mindset of gently folding ('must retain air, must not overdevelop gluten!'), but you must in fact beat the air out of the batter like nobody's business. Knowing when to stop so you don't end up with batter puddles is the key.

For what it's worth, I have tried many macaron recipes over the years, all with varying degrees of fussiness regarding age of the egg whites, texture of the almonds, stiffness of the peaks and so on, but the best recipe I have ever used is the one that does away with most of that nonsense - you can find it here.

Mine used to fail, but now they always turn out well.

The climate doesn't matter. But you have to keep them away from water.

I use following measurements:

• 35 g almond meal
• 50 g icing sugar
• 30 g egg white
• 30 g sugar

Beat the egg whites with the sugar until stiff on low speed, and have patience, as beating on high doesn't stabilize them. Next, fold the other ingredients until the batter flows, the same consistency as the ice cream in McDonalds.

Pipe the macarons, then tap them to let the air out. And then, to make a nice skin, use a hair dryer. Set it on hot and blow at the top of the piped out macarons. Try to blow as much as possible without getting them out of shape. For me, it takes 5 minutes for the shells to dry. The surface becomes like silk cloth, not sticky. It resembles smooth marshmallow skin.

If you don't get that skin, you will get cracks.

I bake mine at 135 degrees for 23 minutes, but that varies with oven.