This was sent to the Chicago Sun TImes by Ivanna Harasovaka:

Pour one gallon skim milk, one quart buttermilk, and two tablespoons of salt into a large enamel pot. Mix well. Cover and let stand for 48 hours. Put the pot on the stove with a very small flame for one hour. It should be warm but it should not boil. Put a colander lined with cheesecloth over another pot and pour the contents through the colander. Let drain for a few hours.