Preheat oven to 350 degrees.
Beat the butter and sugar with the marzipan until smooth.
(Warning! Check the marzipan before you buy it!)
Add egg yolks and almost all the egg whites (reserve a little of the egg whites for later).
Beat until fluffy.
Work flour into batter until smooth; add extra flour if
necessary.
Form into balls & flatten.
Place on greased cookie sheet.
Brush with remaining egg white and sprinkle with cinnamon
sugar.
Bake for 12-15 minutes, until edges and bottoms are browned.
Use a timer or watch carefully - these burn quickly.