Add shortening and salt to boiling water. Reduce heat and add flour, all at once and stir vigorously until mix forms balls around spoon, leaving pan clean. Remove from heat. Add eggs one at a time, beating each one thoroughly. Continue beating until thick and shiny. Shape on ungreased cookie sheet using teaspoon. Bake at 450 degrees for 20 minutes. Reduce heat to 350 degrees and bake 20 minutes more. Cool, make slot and fill.