WALNUT BABKA

Steps:

• Dough: Combine the milk and yeast in the bowl of a stand mixer fitted with the dough hook attachment. Add flour, eggs, sugar, butter, vanilla, and salt, and beat on low speed until ingredients are evenly combined, about 4 minutes. Increase to medium speed and mix 2 minutes more. Turn out dough onto a lightly floured work surface and finish kneading it by hand, about 2 minutes. Form dough into a square. Place on a baking sheet and cover tightly with plastic wrap. Let stand at room temperature 1 hour, then refrigerate dough at least 1 hour or up to 8 hours.
• Place chilled dough on lightly floured work surface. Using a rolling pin, shape dough into a 10-by-28-inch rectangle about 1/4 inch thick.
• Filling: Using a pastry scraper or spatula, evenly spread butter over surface of dough. Sprinkle with sugar, cinnamon, walnuts, and currants or raisins. Using rolling pin, gently roll over filling ingredients to adhere filling to dough.
• Beginning with a long side, roll dough into a tight log. Flatten the log with the rolling pin until it is 40 inches long. Using a pizza wheel, cut log crosswise into 3 equal pieces. Then cut one of the thirds in half lengthwise. Position cut sides of dough on work surface so they are facing the same direction. Place one piece of dough on top of the other to form an X. Twist dough on each side of the X, beginning in center and working toward end to form a spiral. Transfer to a 9 1/2-by-3 1/4-by-2 1/2-inch loaf pan. Repeat process with remaining dough and two more loaf pans. The dough should fill the pans lengthwise as much as possible and only come halfway up the sides of the pan. Cover with a dry, clean kitchen towel and let dough rise until doubled in bulk, about 1 hour.
• Meanwhile, preheat oven to 375 degrees. Uncover dough and bake, turning halfway through baking time, until golden brown, 30 to 35 minutes (if using a convection oven, bake at 350 degrees for 25 minutes).
• Syrup: While loaves are baking, bring sugar and water to a boil over high heat; reduce heat and let simmer 2 minutes. Remove from heat; let cool.
• When loaves are removed from oven, transfer to a rimmed baking sheet fitted with a wire rack. Immediately brush generously with syrup. (You will have extra syrup for another use.) Let babka cool before serving.