Beat the egg whites and salt until soft peaks form.
Slowly sift in the powdered sugar, pour lemon juice, and continuing to beat until the mixture is stiff and glossy.
Remove about a third (1/3) of the meringue mixture and set aside to use for the topping.
In the rest of the meringue beat in vanilla. In a separate bowl mix ground almonds, cinnamon, and lemon zest. Fold the ground almond mixture into the remaining meringue with vanilla to make a stiff, slightly sticky dough. Put the dough in the refrigerator at least 1 hour.
Preheat oven to 150 C (300 F). Line baking sheets with parchment paper.
To form the stars, put the dough on a piece of baking paper lightly dusted with icing sugar and dust the top of the dough with sugar, too. Place the second sheet of parchment on top of the dough and roll out to about 0.7 cm (1/4 inch) thick (the dough is a little sticky, so the parchment makes it easier to roll). Peel off the top sheet of parchment and use a star-shaped cutter to cut out as many cookies as possible.
Place them on your prepared baking sheets.
Using the reserved meringue mixture, spread a small amount onto the top of each cookie, covering the entire top – you may need to add a few drops of water to make the meringue a little easier to spread.
Put the baking sheet in the oven and bake for 12-15 mins until the meringue is set but not browned. Store in a sealed container for up to 2 weeks.