"A traditional German christmas cookie that has a buttery rum and almond flavoring. They look simple but taste like a warm Christmas on a cold snowy day. Store in an airtight container for up to 1 week."
Preheat oven to 350 degrees F (175 degrees C). Line baking sheets with parchment paper.
Sift 4 cups plus 2 tablespoons flour and baking powder onto a pastry board.
Make a well in the center of the flour mixture; add white sugar, almonds, eggs, and rum. Mix in flour from the sides of the well to form a thick paste. Drop butter pieces into the flour. Knead dough, starting from the middle, until firm and smooth.
Roll out dough to 1/8-inch thickness on a floured work surface. Cut into shapes using 3-inch cookie cutters. Transfer to the prepared baking sheets using a spatula.
Bake in the preheated oven until edges are golden, 8 to 12 minutes. Transfer to wire racks to cool slightly, about 5 minutes.
Mix confectioners' sugar, rum flavoring, and water together in a bowl to make icing. Spread icing over warm cookies. Place 1 almond half on top of each cookie.