Preheat the oven to 325°F (163°C). Line two baking sheets with parchment paper.
In a large bowl, cream the softened unsalted butter and granulated sugar together until light and fluffy, about 3 to 4 minutes.
Add the almond extract to the butter and sugar mixture and mix until combined.
In a separate bowl, whisk together the all-purpose flour, finely ground almonds, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing gently until a soft dough forms. Do not overmix.
Turn the dough out onto a lightly floured surface and roll it to about 1/4 inch thickness.
Use a cookie cutter or knife to cut the dough into desired shapes (about 2 inches in diameter).
Place the cookies on the prepared baking sheets about 1 inch apart.
Lightly press sliced almonds onto the tops of each cookie.
Bake in the preheated oven for 18 to 20 minutes, or until the edges are just beginning to turn golden.
Remove the cookies from the oven and allow them to cool on the baking sheets for 5 minutes.
Transfer the cookies to a wire rack to cool completely before serving or storing.