In a small saucepan, melt butter with sour cream and sugar. Set aside to cool slightly.

Dissolve yeast into warm milk. Let sit 15 minutes until mixture gets very frothy.

In an electric mixer fitted with the dough hook, combine butter mixture, yeast mixture, eggs, flour, and salt. Knead together to form a soft dough (it’s okay if it’s a little sticky). Refrigerate eight hours.

Add all ingredients to a bowl and blend using an immersion blender.

Divide dough into four parts. Roll out each part to the size of a standard cookie sheet, 13×18 inches. Cut each part into five squares measuring six inches each.

Spread filling on each square, leaving the edges empty. Roll up, jelly-roll style. Twist two of these rolls together to form a babka and place in a greased mini loaf pan. Let rise 30 minutes.

Preheat oven to 350 degrees Fahrenheit.

Brush babkas with beaten egg. Bake 30 minutes or until light golden.

Combine all ingredients. Brush some of the glaze on warm babkas and drizzle with remaining glaze once babkas have cooled.