Grate potatoes and onion in food processor or by hand. Rinse under cold water, and squeeze out liquid. Mix with beaten eggs, schmaltz or oil. and salt and pepper, (if using).

Put balls of aluminum foil on the bottom of your crock pot, (this keeps the kugel from burning on the bottom). Almost cover with water, about ½ to ¾ of the way up the aluminum balls. Use a crock pot liner. Fill half of the crock pot liner with your potato kugel mixture. 

Cut meat in half and place over kugel. Put remaining potato mixture over the meat. Place cooking bag on top of the aluminum balls, and close crock pot liner with a loose knot. Cover, turn crock pot to low heat overnight. I usually start mine about noon the day before Shabbos.