Blend Natvia in a high-speed blender until the consistency of icing sugar; reserve 2 teaspoons.
Beat butter and powdered Natvia in a small bowl with an electric mixer until light and fluffy. Beat egg yolk, juice, rind and vanilla. Stir in sifted flours, soda and spices, adding half of the husks to the bowl, to form a soft dough. Knead dough on a floured surface until smooth. Divide dough in half; enclose in plastic wrap and refrigerate for 1 hour.
Roll each portion of dough between sheets of baking paper until 3mm thick. Freeze for 15 minutes to firm.
Preheat oven to 180C. Line two oven trays with baking paper.
Cut 12 large, six medium, eight small and eight smaller stars with cutter, re-rolling srcaps of dough as necessary. Place the two smaller-sized stars on one tray and the medium and large stars on a second tray.
Bake the larger stars for 15 minutes and the smaller stars for 12 minutes, or until lightly coloured; cool on trays.
Draw a 25cm round on a piece of baking paper; turn paper, marked-side down, onto a serving board. Following the shape of the marked circle, arrange stars into a wrath shape; start with the large stars on the bottom, then top with medium, small and smaller star, slightly overlapping them.
Just before serving, dust with reserved sifted powdered Natvia.