These shortbread cookies are known as Jan Hagel, a traditional Dutch cookie. They are Sugar Cookies decorated with almond slivers, and pearl sugar. A simple recipe that will take less than 40 minutes .
Mix butter, sugar and salt in a bowl, add egg yolk and mix again, In a separate bowl mix flour, baking powder and cinnamon. Add flour mixture to butter mixture. You'll have a crumbly mixture that easily comes together when you knead it.
Lightly flour work surface and roll the dough until you have a 6 x 9-inch rectangle that is about 1/8 inch. Place the dough on a baking sheet covered with parchment paper. (NOTE 1)
Brush dough with whisked egg and sprinkle with almond slivers and pearl sugar. Press the topping gently into the dough. Use your hands or a rolling pin. (NOTE 2)
Bake 20-25 minutes in the oven. (NOTE 3)
Take the cookies out of the oven and cut them while they are still warm. Allow the cookies to cool completely on a wire rack.
Notes
If the dough is too sticky to roll our, wrap it in some plastic wrap and cool it in the fridge for at least 1 hours.
Be gentle when you press the almonds and sugar into the dough. You don't want the dough to stretch out and become thinner.
When you bake them close to 20 minutes they are a little chewy, if you bake them longer they become more brittle.