Butterbredele (Alsatian Butter Christmas Cookies)

Instructions

1. Beat the egg, sugar and vanilla together until well combined.
2. Rub the flour, baking powder and soft butter between your fingertips until the mixture looks like damp sand.
3. Add the egg mixture and lemon zest and mix until a smooth dough forms. Do not overwork it.
4. Shape into a disk, wrap and chill at least 1 hour.
5. Heat the oven to 350 F (175 C) and line two sheets with parchment.
6. Roll the dough on a lightly floured surface to about 1/8 inch (4 mm) thick and cut out stars, hearts and trees.
7. Place on the sheets, brush the tops with the egg yolk mixture, and bake 10 to 12 minutes until light golden at the edges.
8. Cool on the sheet for 5 minutes, then move to a rack to crisp up.