Heat the milk in a saucepan until lukewarm. Pour the milk into the bowl of a mixer. Add the yeast and 1/2 teaspoon of the sugar and let it become very foamy, about 10 minutes. Beat in the butter and the egg yolks one at a time until combined.

Mix in the remaining 5 Tablespoons of sugar, lemon zest and sour cream and beat until combined. Slowly add in the flour one cup at a time. Mix together on medium-low speed stopping the machine to scrape down the sides of the bowl.

Slowly add the rest of the flour and mix until combined. Stop the machine as you add each cup of the flour to scrape the sides of the bowl and incorporate the flour. Mix on low speed until dough is incorporated. Add flour if needed 1 Tablespoon at a time. The dough will be a little sticky but also firm.

Form the dough into a ball and place into an oiled bowl (when I put the dough in the bowl I swish the dough around the bottom of the bowl and then flip it over so all of the dough is covered in a light film of vegetable oil). Cover with plastic wrap and let it rise at room temperature until doubled in size (about 1-1 1/2 hours).

In a small bowl, mix together the walnuts, sugar, raisins, brandy and milk until combined; set aside.

When the dough is ready:

Preheat oven to 325 degrees. Divide the dough into 3 balls. On a floured surface, roll out the first ball into a 9-by-13-inch rectangle. Spread 1/3 of the walnut mixture evenly over it and roll it up into a 13-inch-long log.

Dab some of the beaten egg white along the seam and place the log seam side down onto a well-buttered 9-by-13-inch pan. Repeat with the remaining dough. Cover and let rise for 45 minutes.

Brush the whole beaten egg over the tops of the loaves. Bake until lightly browned, about 45 minutes. Transfer loaves to a wire rack to cool for 15 minutes. Dust with confectioner’s sugar. Slice and serve warm or at room temperature.