These are standard Russian peasant staples, and there is an old Russian saying that goes, "Shchi ee kasha, pisha nasha" which means "Shchi and kasha, that's our fare".
This novel was writen in his later lifePip, a boy of the marshes, is being "raised by hand" by his shrieking harridan of an older sister and her seemingly doltish husband, the blacksmith Joe Gargery.