In the stand up mixer with the dough hook attachment, combine the flour, sourdough starter, sugar, salt, eggs and milk. Knead for about 10 minutes, let the dough rest, then add the butter a little at a time, continue to knead between each addition. Then knead for 5 minutes until the dough is smooth but still a little sticky. Leave the dough covered in warm draft free area for about 2 hours, then refrigerate over night.
Remove the dough from the fridge and roll on a floured flat surface into into a rectangle (10x18 inches/25x45cm), about ¼ inch thick. Spread with your favourite store bought or homemade Hazelnut Cream Spread (Nutella) or Chocolate Cream Spread, be sure to leave a bit of a border (½ inch/ 1 cm) sprinkle with nuts and chocolate chips if desired.
Grease and flour 2 loaf pans (8-9 inches/ 20-22cm), a bundt or tube pan (9½ inch / 24cm) or a pie dish (8-9 inches / 20-22cm).
Roll the dough up lengthwise, then cut the dough in half again lengthwise, twist it to form a braid. The braid is quite long so you can cut it in half and make two loaves or place it in a the prepared pan and join the ends.
Cover the pan and let rise in a warm draft free area until doubled in bulk, approximately 3-6 hours.
Pre-heat oven to 375F (190C).
Brush the risen dough with an egg wash and bake 25 minutes, lower the oven to 350F (180C) and continue to bake 5-10 minutes or until golden. Move the Babka immediately to wire rack to cool before serving. Enjoy!
EGG WASH
In a small bowl beat together the egg and water.
Notes
For room temperature ingredients, remove from the fridge 30-60 minutes before using.Babka will be best consumed the same day, but it will last once it is cooled completely, stored in an air tight container or wrapped in plastic at room temperature. It should keep for up to three days.To freeze the bread, make sure it has cooled completely then wrap it in plastic wrap then either wrap again in foil or place in a freezer safe bag or container. It will keep for up to a month in the freezer.