In the work-bowl, pour the water, the yeast and 2 tablespoons of flour and mix with a hand whip until the ingredients are homogenized. Leave it for 5-10 minutes to leaven.
Pour 60 gr. granulated sugar into the cooking machine, the mahlab, the mastic and the cardamom and mix well for 2 minutes until the mastic dissolves.
Addthe zest of the orange and the spices into the work-bowl of the mixer, add the rest of the sugar (100 gr), the flour, the eggs, the milk and finally the 50 gr. butter.
Mix with the dough hook for 2-3 minutes at slow speed and then at high speed for another 10-15 minutes.
Finally, add the remaining 50 gr. butter and a pinch of salt. Put the salt at the end to destroing our yeast.
Mix for another 2 minutes until fibers are created in our dough. When the butter is absorbed, remove the work-bowl from the mixer.
Put the dough in a bowl spread with olive oil. Wrap with plastic wrap and leave for 1-1: 30 hours until its volume is doubled.
Then, cut the dough in half and each piece into 4 equal smaller ones.
Open with hands in long strips of 30 cm. With the rolling pin shape every cord 4-5 cm thick so that it can be filled.
Spread with a teaspoon the pureed chestnut along the cord. Each cord will get around 2-3 tablespoons of the puree.
Roll each cord to cover the filling.
Push the edges well and roll on the counter.
Form a “braid” with 4 cords. Join the four edges of the stripes. To be able to make the braid, number the strips from 1 to 4
Place the dough strip 4 over the dough strip 2. 1 over 3 and 2 over 3.
Repeat the process as many times as necessary until the braid is formed. You will create 2 tsourekia this way.
Leave it for 30 minutes to leaven.
Preheat the oven to 150° C in fan mode.
Brush with mixture of a yolk with 1 tablespoon water and bake in oven for 45-60 minutes.
Let the tsoureki cool down and spread with the brush the white chocolate on its surface.
Form little stripes with dark chocolate, let it cool and serve.