Put all of the ingredients in a small saucepan over a medium heat. Check often until the mixture begins to simmer. Lower the heat oand cover the pan. Cook for 40 minutes.

Strain the mixture into a mixing bowl. Be sure to squeeze out all the liquid. Put the liquid into the fridge for 2 hours. The butter will float to the top and harden, making it easy to seperate from the water. Discard the water.