Place cold butter into the Thermomix bowl and chop 5 sec/speed 5.
Add the sugar, salt and vanilla and combine 10 sec/speed 10. Stop and scrape down the sides of the bowl and repeat. If the mixture is not starting to come together as one, keep blending on speed 8 until you have a semi smooth mix happening. Insert the Butterfly.
Whip 2 min/Butterfly/speed 4. Remove Butterfly.
Add egg, yolks, cream of tartar, baking soda, flour and chai mix and blend 10 sec/speed 5, scrape down and repeat until you have a nice sticky dough. Add the chocolate chips and stir through with a spatula. Transfer to a regular mixing bowl and refrigerate for at least 30 minutes.
Preheat oven to 180°C and line 2 trays with baking paper.
When ready to cook prepare a small bowl with extra coconut sugar and a separate bowl with a little chai mix. Roll about 2 tbsp of dough at a time into a ball and dip just the tops into the sticky chai. Then toss gently in the sugar. Place on the trays. Repeat until the dough is finished.
Bake until golden and fragrant, about 8-10 minutes. Cool 10 minutes on the trays before transferring to a wire rack.