From 1922:

During the potato show held in Bronson’s garage Friday and Saturday potato pyramids were served by Ruth Kennedy, home demonstrator with the extension service. As many inquiries were made concerning the recipe used, we are publishing it today. It is one of several sent out by the state college. The recipe follows:

To one cup of well-seasoned mashed potato add one egg yolk. Beat until light. Take up by tablespoonfuls and form into pyramid shapes by pointing one end, and broadening the other as base. Set them on a greased tin, brush over with beaten egg, and when ready to serve, brown lightly in the oven. Mashed potatoes are more easily handled if shaped after a meal is over, while still slightly warm.