Mix the butter, sugar, lemon zest and the egg in a bowl. Add the flour and baking powder little by little. Knead. Cover the dough ball with plastic wrap and set aside in the fridge for an hour. Meanwhile, preheat your oven to 374 degrees F (190 degrees C).When your dough has rested, open up the plastic wrap and give it another quick knead, and then push out into a flattish shape of about 1/4 inch thick (5 mm) with the balls of your hands. You can, of course, do this on a floured surface, but I just keep it on the plastic wrap. Using a star or wreath shaped cookie cutter, cut out your cookies and use the back of a wooden spoon to make a hole in the middle. Place the cookies on a greased cookie sheet, brush with the egg and decorate with almond slivers and glace cherries. Bake for 10 – 15 minutes or until golden brown. Makes about 30 cookies.
Feel free to use a stand mixer with a dough hook to knead the dough.
If the dough gets too sticky for the cookie cutter, just put it back in the fridge for a few minutes.