In a medium bowl, stir together flour and salt. Cut in chilled butter until the texture of the mix is mealy with pea sized lumps. (I grated my butter first and it worked awesome!) Add ice water gradually while stirring with a wooden spoon until dough forms a ball. Cover your dough and place in the refrigerator.

To make filling, in a small bowl, mix together the almond paste and sugar. Add the egg and mix well.

Chill dough and filling for 24 hours.

Preheat oven to 375 degrees F.

On a lightly floured surface, roll out the dough to 1/4 to 1/8 inch thickness, making the shape as square as possible. Cut the dough into strips 6 inches long and 1 1/2 inches wide (about the width of a ruler). Using a pastry bag or a strong plastic bag with a small hole cut from the corner, pipe almond filling down the center of the strip starting halfway down. Fold the top half of the strip down over the almond filling to match the bottom.
Shape strips into desired letters, brush with milk and sprinkle with sugar.

Bake in preheated oven for about 20 minutes or until golden brown. If you are using all butter in your recipe, check after 15 minutes. Remove from the oven and cool on a wire rack.