For the “tsoureki” dough:
1/4 cup & 1/2 teaspoon sugar
1/8 cup lukewarm water
1/2 tablespoon dry yeast
1/4 cup lukewarm milk
2 & 1/2 cups all purpose flour, more or less
1/8 tablespoon mahleb powder
1/4 tablespoon mahleb kernels
1/3 cup water, for boiling the mahleb kernels
1/8 tablespoon mastic powder
pinch of vanilla powder
pinch of salt
2 eggs at room temperature
1/4 cup unsalted butter, melted
1/2 teaspoon orange zest
1 tablespoon fresh orange juice, at room temperature
For the chocolate filling:
1 cup hazelnuts, toasted and skin removed
1/2 cup brown sugar
1 teaspoon vanilla extract, liquid form
28 grams semi-sweet chocolate, melted
1. In a small bowl, stir together the yeast, 1/8 cup of lukewarm water and 1/2 teaspoon of sugar until the yeast and sugar have dissolved. Cover the top of the bowl with plastic wrap and let it rise for ten minutes until frothy.
2. In another bowl, mix together the dry ingredients.
3. In a small pot on the stove, boil 1/3/ cup water and the whole mahleb kernels. Once the water has boiled, take 1 tablespoon of the boiled water and let it cool (until lukewarm temperature) in a small bowl.
4. In another bowl, beat the eggs, sugar and 1/2 teaspoon of orange zest in a mixer on high speed for 7 minutes until the mixture appears creamy.
5. In another bowl, stir together the melted butter and the milk.
6. Make a small dip in the middle of your dry ingredients. Then add the yeast mixture, creamed sugar mixture, milk mixture, 1 tablespoon lukewarm mahleb water and orange juice and begin to mix the ingredients with your hands until a soft dough is formed. You may not need all the flour, or you may need a little more for a soft dough to form. Vigorously knead the dough for ten minutes until it becomes smooth and elastic. If the dough sticks to table, add a little more flour. Place the dough in a bowl, cover it with plastic wrap and a blanket and let it rest for 2 hours, until it has doubled in size.
7. Just before the dough is ready, make the chocolate filling. Add the hazelnuts and sugar into a food processor and grind the hazelnuts until a paste is formed (about 3 minutes). Then add the hazelnut oil, egg, vanilla and melted chocolate and process until smooth (about 1 minute).
8. Roll the dough out into a large rectangle, about 1/2 an inch thick. Spread the chocolate filling all over the rectangle. Begin to roll up the dough. Once you have formed a long roll use a serrated knife to cut the long roll into 16 one inch thick rolls.
9. Butter and flour a large bundt pan. Arrange 8 rolls in the bottom of the bundt pan, ensuring that they overlap each other. Repeat with a second layer on top of the bottom layer. Cover with a kitchen towel, and let rise for 1 & 1/2 hours, until the dough has doubled in size.
10. Preheat your oven to 160C. Bake for 30 to 35 minutes. Remove and let cool for 20 minutes in the bundt pan. Then remove cake from the bundt pan and let completely cool. Decorate with sifted icing sugar and serve.