In the origin rillons were the scraps of meat left at the bottom of the big pan in which the meat of a whole pig was cooked for the purpose of making fat for the needs of the household. They were then seasoned and kept in small pots. But those days are over, and rillons are now made on a smaller scale.
Remove them from the fire and squeeze through a sieve. Taste them, add more seasoning if necessary, put them back in the saucepan and cook a few minutes more. Then put them in earthenware pots and pour slowly the melted fat over them, so that it fills the tiny spaces left in the rillons. Go on pouring till you have on the top à layer of pure fat about half an inch thick. Cover with paper and the lid. Rillons are very good cold as a kind of coarse pâté, as hors d’Œuvre, and also used for different dishes.