• 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.