The average gyoza takes 5 to 15 minutes to cook. The exact cooking time will vary depending on the size of the gyoza, the ingredients, and the way the gyoza are cooked.

First of all, the size of the dumpling will affect the cooking time. Regular frozen dumplings usually take 10 to 15 minutes to cook through because of the thicker skin and more filling. Self-made dumplings usually take only 5 to 8 minutes to cook through, because the skin is thin and there is less filling.

Secondly, the ingredients used to cook the dumplings will also affect the cooking time. For example, dumplings made with ingredients such as pork and cabbage take a relatively short time to cook, while dumplings made with meats that are not easy to cook, such as beef and lamb, take longer.

In addition, the way you cook the dumplings also affects the cooking time. Gyoza cooked in boiling water usually need to be cooked for about 10 minutes, while those cooked in cold water need to be cooked for more than 15 minutes to be cooked through. The dumplings need to be stirred from time to time to prevent them from sticking together.

Finally, you need to boil the water before cooking, whether it's frozen dumplings or dumplings you've made yourself. Also, to prevent the dumplings from sticking together during the cooking process, you can add an appropriate amount of salt or cooking oil to the water. At the same time, the boiled dumplings need to be fished out and drained in time to prevent them from sticking together or becoming too soft.