Dough

1. Warm the milk and butter to about 100°F (38°C), or until slightly warm to the touch. Transfer to a large mixing bowl and add 2 cups of flour, the sugar, egg, yeast, and salt. Fold together until a dough forms. If it is too sticky, add more flour by the tablespoonful until it begins to form a ball. Turn out onto a lightly floured surface and knead until smooth and elastic, about 5–8 minutes. Form into a ball.
2. Transfer to a lightly oiled bowl, cover, and let rise in a warm spot until doubled in volume, about 2 hours.

Assembly

1. Preheat the oven to 375°F (190°C).
2. In a small bowl, stir together the brown sugar, cinnamon, and cardamom. Add the softened butter and mix into a spreadable paste.
3. On a lightly floured surface, roll the dough out into an approximately 11 × 15-inch rectangle. Using an offset spatula, spread the brown sugar-spice mixture uniformly over the dough, leaving a ½-inch border around the edge. Sprinkle the finely chopped chocolate evenly over the filling. Starting from one long side, roll the dough into a log.
4. Using a sharp serrated knife, cut the log in half lengthwise and turn the cut sides upward. Pinch one end of the two strands together, then twist them around each other, keeping the cut sides facing up at all times. Pinch the remaining end. Form the twist into a circle and transfer to a lightly greased cast-iron pan or 9-inch round cake pan. Brush with the beaten egg and sprinkle evenly with raw sugar.
5. Bake for 25–30 minutes, until dark brown and fragrant. Run a knife around the outside of the pan and rest for 15–20 minutes before serving. Best served warm, plain or with ice cream.