It's the same on JL. As mentioned upthread, by serving it rock hard, that allows everyone to have it as hard/soft and as warm/cold as they want. IME you do'nt have to wait the whole 20-30 minutes. After not too long, the top layer will be soft enough to eat. Then, as you eat off the top layer and the next layer is exposed, that, too, hits the relatively warm cabin air and starts to soften.