1, there was ice cream in the Tang Dynasty, but it was called Sushan or Sushan at that time. This kind of food is made of cheese, ice, honey, etc.
2. This is described in detail in Wang's Su Heshan Fu. First, he heated the cheese until it melted, then dripped it on plates and other utensils, made it into a hill shape while pouring it, and finally put it in the freezer for freezing.