Make the Tangzhong: In a small saucepan, combine the 2 tablespoons of bread flour and ⅓ cup of water. Cook over medium heat, stirring constantly, until thickened (about 3-4 minutes). Remove from heat and let cool completely.

Prepare Dough: In a stand mixer bowl, mix together the 2 cups of bread flour, ¼ cup of sugar, ½ teaspoon of salt, and 1½ teaspoons of active dry yeast. Pour in the ⅓ cup of room temperature milk, add 1 large egg, and the cooled tangzhong. Mix on low speed for 5 minutes, then gradually add 5 tablespoons of softened butter and mix until smooth and elastic (around 15 minutes).

Ferment: Transfer the dough into an oiled container, cover it with plastic wrap, and refrigerate overnight for 8-12 hours.

Make Filling: Melt 2.3 oz of dark chocolate and 4 tablespoons of butter together. Once melted, sift in 3 tablespoons of powdered sugar, 2 tablespoons of cocoa powder, and a pinch of sea salt, mixing until you have a smooth filling. Stir in ½ cup of toasted and chopped pistachios.

Shape Babka: Roll the chilled dough into a 12x15 inch rectangle. Spread the chocolate filling evenly over the dough, then sprinkle with additional pistachios. Roll the dough tightly, slice the log lengthwise, and twist the two halves together.

Proof: Place the braided dough into a greased loaf pan, cover, and let it rise in a warm spot until puffy (about 60-90 minutes).

Bake: Preheat your oven to 350°F (180°C). Bake the babka for 30-35 minutes, or until golden brown and the internal temperature reaches 190°F (88°C).

Sugar Syrup: While the babka bakes, combine 3 tablespoons of water and 2 tablespoons of granulated sugar in a small saucepan. Simmer until dissolved, and brush over the hot babka as soon as it comes out of the oven.

Cool: Let the babka cool in the pan for about 20 minutes before transferring it to a wire rack to cool completely.