serve piping hot.

From 1914:

Cook spinach until tender, about twelve minutes. Put in colander and chop fine. Allow to drain. Salt to taste. Mix with chopped hard boiled eggs, four eggs for each peck of spinach used. Butter brown betty cups and put in the spinach, dot tops with bits of butter and a few bread crumbs.
Put in oven for five minutes. Turn onto platter and serve piping hot.