In a large bowl, combine the all-purpose flour, cold butter cut into cubes, powdered sugar, almond extract, and salt. Mix until it resembles coarse crumbs.

Add in the egg yolk and mix until a dough forms. Wrap in plastic wrap and refrigerate for at least 30 minutes.

On a floured surface, roll out the chilled dough into a rectangular shape, about 1/8-inch thick.

Spread the almond paste evenly over the surface of the rolled dough.

Fold the long sides of the dough into the center, then fold the dough again to create layers. Cut into squares or triangles.

Place the cut pastries on a baking sheet lined with parchment paper. Brush with milk and sprinkle sliced almonds on top.

Preheat your oven to 350°F (175°C) and bake for 25-30 minutes, or until golden brown.

Let them cool slightly before digging in!