Preheat oven to 250F. Place 1lb of fat (leaf fat, fat back or pork fat
pieces cleaned of skin and meat and finely diced) in an ovenproof dish. Add
enough cold water to partially cover. Put in oven (or over very low flame)
for 40 minutes, or until fat has melted, stirring occasionally to prevent
it from browning or sticking. Remove from oven and strain through a
cheesecloth into a heat proof container. Set aside. When fat has set into a
smooth white shortening, cover and refrigerate. Will keep for 3 months.
From Amanda (ahl5 at PANTHEON.YALE.EDU)