The casserole has fast heat transfer, slow heat dissipation, and strong heat preservation capability. Generally, the food in the casserole can still maintain a temperature close to boiling after turning off the fire for 5 to 10 minutes. The casserole can transfer the external heat energy to the internal raw materials in a balanced and lasting way. The relatively balanced ambient temperature is conducive to the mutual penetration of water molecules and food, and can maximize the release of food taste. It is suitable for slow boiling over a small fire.