01 - In a medium bowl, whisk together flour, ground almonds, cinnamon, and salt until evenly combined.
02 - In a large bowl, cream butter and powdered sugar until light and fluffy, approximately 2 to 3 minutes.
03 - Add egg yolk, vanilla extract, and almond extract if using to the butter mixture. Beat until fully combined.
04 - Gradually add the dry ingredients to the wet mixture, stirring until a soft dough forms.
05 - Divide dough in half, shape each half into a disc, wrap in plastic wrap, and refrigerate for at least 1 hour.
06 - Preheat oven to 350°F (175°C). Line two baking sheets with parchment paper.
07 - On a lightly floured surface, roll out one disc of dough to approximately 1/8-inch (3 mm) thickness.
08 - Using a 2-inch (5 cm) round or fluted cookie cutter, cut out cookies. Use a smaller cutter to cut a window shape (heart, star, or circle) in the centers of half the cookies for the top pieces.
09 - Transfer cookies to prepared baking sheets, spacing them 1 inch apart. Re-roll and cut dough scraps as needed.
10 - Bake for 10 to 12 minutes, or until edges are just turning golden. Cool on sheets for 2 minutes, then transfer to a wire rack to cool completely.
11 - Dust the cutout cookie tops generously with powdered sugar.
12 - Spread approximately 1 teaspoon of raspberry jam onto the flat side of each bottom cookie. Gently sandwich with the powdered sugar-dusted tops.