• Gather all the ingredients.

Prepare the sourdough starter (7:30 am)

• Feed the sourdough starter at 100% hydration.

Prepare the dough (4:00 pm)

• In a stand mixer fitted with the dough hook mix all the wet ingredients until well incorporated.
• Sift the flour, salt, and ground cardamom directly into the bowl with the wet ingredients.
• With the mixer on speed 2 mix until you get one cohesive mass and there are no dry lumps visible. Cover and leave to rest for 15 minutes.
• With a mixer on speed 4-5 knead the dough until the bowl starts to get cleaner and the dough makes a thumping sound (about 8 minutes). Scrape the sides of the bowl as needed. Check the gluten development by using the windowpane test.
• With the mixer on speed 4, add butter incrementally, about one tablespoon at a time.

  Continue mixing until the dough comes back together and forms a cohesive mass and the sides of the bowl of the mixer is clean (about another 6 to 8 minutes).
• Transfer the dough to a clean lightly buttered mixing bowl. Do a couple of coil folds to form a nice ball from the dough. Cover and rest for 1 hour.
• Perform two coil folds. Cover and rest for 1 hour.
• Perform two coil folds. Cover and rest for 1½ hours.

  Transfer the dough to the fridge for overnight fermentation.

Prepare the filling (8:00 pm)

• In a medium saucepan whish together the carob and the milk until there are no clumps of carob visible. Add the butter, sugar, and brown sugar and mix well to incorporate. Cook over medium heat for 5 minutes until the mixture is boiling slowly. Stir the mixture continuously.
• Take off the heat and add the vanilla extract, clementine zest, and the Port wine. Mix to incorporate the ingredients.
• Transfer to a clean glass or ceramic bowl, cover and let cool to room temperature.

Rolling & Shaping (next day, 8:00 am)

• Lightly dust the working surface with the flour. Roll out the dough into a rectangle the size of 50cm by 64cm (20in by 25in). Thedough should be about 0.5cm (⅕in) thick.
• Spread the filling evenly on the surface of the dough using an icing spatula. Fold the dough into a log by rolling it inwards along the long edge.
• Using the kitchen ruler measure and mark the middle of the log. Cut the dough in half using the side of a plate. Transfer the logs on a tray, cover, and refrigerate for 15 minutes.
• Take the logs out from the fridge. Take one log and cut it in half lengthwise. Flip each of the cut sides so that they are facing up exposing the filling and the layers.

  Twist the halves together, interchangeably, as if braiding them.

  Hold the babka along the long edge and carefully place it in the buttered pan. The edges should naturally fold under slightly.

  Repeat with the second log.
• Cover both babkas and let them proof for 2 hours at about 26ºC (78ºF).

Baking & Serving (next day, 10:30 am)

• Preheat the oven at 180ºC (356ºF)
• Brush both babka's with the egg wash (mix an egg with the milk) and sprinkle some pearl sugar on top (if using).
• Bake babka's at 180ºC (356ºF) for 35 minutes or until very golden in color and the inserted wooden skewer comes out clean. (Note 2)