01 - In a large mixing bowl, blend together finely ground almonds, powdered sugar, ground cinnamon, and salt until evenly incorporated.
02 - In a separate bowl, beat egg whites with an electric mixer until stiff peaks form. Gently fold in vanilla extract and lemon juice.
03 - Carefully fold the whipped egg white mixture into the almond mixture to form a cohesive, sticky dough.
04 - Wrap the dough tightly in plastic wrap and refrigerate for at least 1 hour to allow it to firm up.
05 - Preheat oven to 325°F. Line baking sheets with parchment paper.
06 - Between two sheets of parchment paper, roll out the chilled dough to 1/2-inch thickness.
07 - Using a star-shaped cookie cutter, cut out stars and transfer them to prepared baking sheets.
08 - For the icing, whisk the egg white in a bowl until frothy. Gradually add powdered sugar and lemon juice, continuing to whisk until thick and smooth.
09 - Brush a thin, even layer of icing onto each star-shaped cookie using a pastry brush.
10 - Bake in the preheated oven for 10 to 12 minutes, until the icing is set and the cookies are firm but not browned.
11 - Transfer baked cookies to a wire rack and allow to cool completely before serving or decorating further.