Place aquafaba (liquid from a can of chickpeas) and guar gum in a narrow bowl.
With a handheld mixer whip for 5 minutes, or until stiff peaks form.
Add 25 g powdered sugar and whip for another 2 to 5 minutes, or until the mixture resembles thick marshmallow fluff or very stiff whipped cream.
Place remaining ingredients in a large bowl and mix well.
Add whipped aquafaba and use a spatula to fold it into the nut mixture. This will take one or two minutes. Your dough will be stiff and sticky.
Preheat the oven to 150°C and line two baking sheets with parchment paper.
Roll the cinnamon star dough out 1/2 cm thick) between two sheets of plastic wrap.
Cut out as many cookies as possible.
Form the dough scraps into a ball, roll out again and cut out more cookies until no dough is left.
Place on a baking sheet. Bake one sheet at a time for 11 minutes or until the bottoms are only slightly browned.
Let cool on a cookie rack.
To make the frosting, place powdered sugar in a small bowl and add lemon juice by the teaspoon. You'll want a stiff frosting that can be spread but will not drip off your cookies.
Dip the cookies upside down into the frosting and let dry on a cookie sheet.
Store in an airtight container. The cookies will soften after a day.