Step 1: Prepare the Dough
In a medium bowl, whisk together the flour, ground almonds, cinnamon, and salt. Set aside.
In a large mixing bowl, beat the softened butter and granulated sugar together until light and fluffy, about 3 minutes.
Add the egg, vanilla extract, and almond extract (if using), and beat until well combined.
Gradually add the dry ingredients to the wet ingredients and mix until a soft dough forms.
Divide the dough into two portions, flatten each into a disk, and wrap them in plastic wrap. Chill the dough in the refrigerator for at least 1 hour.
Step 2: Roll Out the Dough
Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.
On a lightly floured surface, roll out one portion of dough to about 1/8-inch thickness.
Use a heart-shaped cookie cutter to cut out heart-shaped cookies and place them on the prepared baking sheets.
For half of the cookies, use a smaller round cutter (or small heart cutter) to cut out the center of each cookie to create a window for the jam filling.
Step 3: Bake the Cookies
Bake the cookies in the preheated oven for 8-10 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheets for 5 minutes, then transfer them to a wire rack to cool completely.
Step 4: Assemble the Cookies
Once the cookies have cooled, spread a thin layer of jam on the flat side of the whole heart-shaped cookies.
Dust the cookies with the cut-out centers with powdered sugar using a sifter.
Carefully place the powdered sugar-topped cookies on top of the jam-covered cookies to create a sandwich.
Step 5: Serve and Enjoy
Let the jam set for a few minutes before serving to ensure the cookies hold together.
Serve immediately or store in an airtight container at room temperature for up to a week.