10-20 minutes. Generally, the zongzi frozen in the refrigerator is cooked first and then frozen, and it doesn't take too long to cook. If you like soft glutinous rice, you can cook it for about 15-20 minutes, and if you like hard rice, you can cook it for about 10- 15 minutes. Therefore, it takes 10-20 minutes for the dumplings frozen in the refrigerator to be cooked.