Mix together butter (from the fridge and diced), polenta flour, flour, sugar and tangerine zest. When you get a sandy consistency, add the egg and the vanilla extract and work into a dough (if needed add a couple of water tbsp.). Form a dough ball, wrap it in plastic and freeze for about 15 minutes.

Preheat oven to 370-390°F (190-200°C).

Divide the dough in small pieces and work them with your hands into balls. Press each ball between your palms to get a round cookie. Sprinkle basil sugar over a clean surface and press each cookie (one side only) over it. Line cookies on an oven sheet with parchment paper.

Bake cookies 12-15 minutes (until borders get a golden color).