Not That Anyone Should Care

In kosher food you cannot mix milk with meat, which means you cannot use butter in a meal with meat in it, so clarified chicken fat is used in many things as a butter replacer. It's what makes good chopped liver good, and is often found in kosher meat delis in a little bowl on the table like butter would be. Personally, I find it nasty to use that way, but it's a great way to roast potatoes.