Prepare the Dough:
In a large mixing bowl, combine the flour, sugar, yeast, and salt. In a separate bowl, mix the warm milk, melted butter, and eggs until well combined. Gradually add the wet ingredients to the dry ingredients, stirring until a dough forms.

Knead the Dough:
Transfer the dough to a floured surface and knead for about 5-7 minutes until it’s smooth and elastic. Place it in a greased bowl, cover with a clean towel, and let it rise in a warm place for about 1 hour or until it doubles in size.

Make the Cream Cheese Filling:
In a mixing bowl, beat the softened cream cheese and powdered sugar until smooth. Stir in the blueberries and vanilla extract gently, being careful not to crush the blueberries.

Roll Out the Dough:
Once the dough has risen, punch it down and roll it out into a rectangle (about 12×18 inches) on a lightly floured surface.

Spread the Filling:
Spread the cream cheese filling evenly over the rolled-out dough, leaving a small border around the edges. Starting from one long side, roll the dough tightly into a log.

Shape the Babka:
Using a sharp knife, cut the rolled dough in half lengthwise to expose the filling. Twist the two halves together, then shape it into a coil or braid. Place the twisted dough into a greased loaf pan.

Second Rise:
Cover the loaf pan with a towel and let the dough rise again for about 30 minutes until slightly puffed.

Preheat the Oven:
Preheat your oven to 350°F (175°C).

Bake:
Once the dough has risen, sprinkle the optional sugar and cinnamon topping over the top. Bake for 30-35 minutes or until golden brown and a toothpick comes out clean.

Cool and Serve:
Let the babka cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely before slicing.