In the bowl of a stand mixer combine flour, milk, eggs, yeast, sugar, vanilla paste, and lemon zest.

Mix with dough hook and when the dough starts to form, add butter, continue kneading, add the salt.

Knead for 8 minutes until it is a soft smooth dough. Transfer to a greased bowl to rise and cover for 1 hour and 30 minutes until it doubles in size or overnight in fridge.

Prepare a large deep pan with parchment paper. Divide dough into 3 pieces and roll each piece into a large rectangle about 15 inches by 10. Spread chocolate over the dough, slice into 8 thin strips. Place 4 strips one on top of the other. Slice lengthwise in the middle and twist the stacks of strips like a braid. Place on prepared pan and repeat with remaining dough and chocolate spread.

Brush with egg, sprinkle with pistachios, cover and let rise again for 30 minute.

Preheat oven to 375℉/160℃. Place pan in oven and baake 25-30 minutes until nicely golden.

Meanwhile prepare sugar syrup by mixing sugar, water and lemon juice in a saucepan over low heat until sugar is dissolved. After removing breads from the oven, brush very generously with sugar syrup.