Pour in the broth, stir and let it come to a simmer. When it starts to simmer reduce the heat to medium low (3 out of 10). Place an inverted, slightly smaller ceramic plate, into the pot, creating a cover and a top weight. Put the lid on the pot and cook for about 3-4 minutes, do not stir. The simmer should be vigorous but not too vigorous to burn everything. This may take some experimenting to determine the right level of heat.