Preheat your oven to 350°F (175°C) and prepare baking sheets by lining them with parchment paper.
In a large mixing bowl, cream together the softened butter and sugar until light and fluffy. This usually takes about 3 to 5 minutes.
Beat in the egg and vanilla extract until well combined.
In a separate bowl, whisk together the flour, salt, and cinnamon (if using). Gradually add the dry ingredients to the wet mixture, mixing until a dough forms.
Divide the dough in half. Roll out each portion to about 1/8-inch thickness on a lightly floured surface.
Use cookie cutters to cut the dough into desired shapes. Place the cutouts on the prepared baking sheets. Sprinkle with additional sugar and top with a slice of almond or pecan for decoration.
Bake in the preheated oven for 8-10 minutes, or until the edges are lightly golden. Keep a close eye as they can brown quickly.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.