Cream butter and brown sugar with the whisk of the hand mixer. Stir in the eggs one after the other. Mix flour, tartar baking powder, baking powder, gingerbread spice and salt. Using the dough hooks of the hand mixer, briefly stir into the egg-sugar mixture
Mix white sugar and cinnamon. Shape the dough into balls the size of a walnut and turn them in the cinnamon-sugar mixture. Place the balls at a good distance from each other on 2-3 baking trays lined with baking paper. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 8-10 minutes (cookies are ready, even if they still feel soft!). Sprinkle with the rest of the cinnamon mixture and allow to cool. Keep well sealed in tins