Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, powdered sugar, salt, and baking powder.

Add the chilled cubed butter to the dry ingredients. Using a pastry cutter or your fingers, work the butter into the flour mixture until it resembles coarse crumbs.

Stir in the almond flour, ensuring it is evenly distributed throughout the mixture.

In a small bowl, whisk together the egg and almond extract. Pour this mixture into the large mixing bowl with the flour and butter mixture and stir until just combined.

Turn the dough out onto a lightly floured surface and shape it into a disk. Wrap the disk in plastic wrap and chill in the refrigerator for about 30 minutes.

Once chilled, roll out the dough to about 1/4 inch thick and use a round cookie cutter to cut out circles of dough.

Place the circles on the lined baking sheet, spacing them about 1 inch apart and slightly flatten the tops.

Sprinkle sliced almonds on top of each cookie.

Bake for 15-20 minutes, or until the edges are golden brown.

While the cookies are baking, mix the powdered sugar with water to achieve a smooth, drizzle-able consistency for the icing.

Once the cookies are done, let them cool on a wire rack and drizzle the icing over once they have cooled completely.