Jan Hagel Cookies

Step 1
Preheat the oven to 300 degrees F (150 degrees C). Set out two rimmed baking sheets.

Step 2
Beat butter and sugar with an electric mixer in a mixing bowl until light and fluffy. Mix in egg yolk until thoroughly combined and creamy. Add flour and cinnamon and mix until dough is well combined.

Step 3
Spread 2/3 of the dough over one baking sheet; spread remaining dough over half of the second baking sheet. Press down on dough with your fingers, then score with a fork.

Step 4
Whisk egg white and water together in a small bowl; brush lightly over dough. Sprinkle walnuts over top.

Step 5
Bake in the preheated oven for 30 minutes.

Step 6
Remove from the oven and immediately cut into 24 squares or rectangles. Let cool completely on the baking sheets, then remove and separate cookies.