Over low heat, bring cream to a simmer (be careful not to boil over) in a saucepan. Simmer for about three minutes, then add the juice of one lemon, and simmer for another three minutes on very low heat.
Remove from heat and allow to cool in the pan for about 30 minutes.
Place a large coffee filter in a strainer and set the strainer over a bowl. Use a spatula to scrape all of the curdled cream onto the filter.
Place in the refrigerator for one to two days to allow the whey to strain. Remove and place into an airtight container and keep in the refrigerator for seven to 10 days.