First we need to make the dough, because you need to put it in a bag and let it rest in the refrigerator for 30 minutes. And during this time, we will prepare the filling for dumplings.
Make the dough. Sift the flour, add salt and mix. In a bowl, whisk together the egg, butter and a small pinch of salt. Pour hot water, continuing to work with a whisk. Immediately send the mixture to the flour and knead the dough with a silicone spatula (fork). As soon as the dough takes enough flour, spread it on the work surface covered with flour and start working with your hands. Roll the dough into a ball.