Probably original to Russia, Poland, or another location in Eastern Europe, in the United States babka is primarily associated with the Jewish baking tradition. A store-bought babka has usually been baked in a loaf pan, whereas home-made versions are baked in a tube or Bundt pan – there are instructions for both shapes here. Thanks to Mildred Shapiro for sharing her family babka recipe.

Makes two loaves, about 14 1/2-inch slices each

BABKA DOUGH

1 1/4 cups milk

5 teaspoons (2 envelopes) active dry yeast

8 tablespoons (1 stick) unsalted butter, melted and cooled

1/2 cup sugar

1/2 teaspoon salt

6 large egg yolks

2 teaspoons vanilla extract

3 3/4 cups unbleached all-purpose flour (spoon flour into dry-measure cup and level off)

CHOCOLATE FILLING

8 ounces bittersweet (not unsweetened) chocolate, coarsely chopped

1/2 cup sugar

1 tablespoon alkalized (Dutch process) cocoa powder

1/2 teaspoon ground cinnamon

1 cup (about 4 ounces) walnut or pecan pieces, coarsely chopped

Two 8 1/2 x 4 1/2 x 2 3/4-inch loaf pans, buttered and the bottoms lined with rectangles of parchment or buttered wax paper cut to fit

Warm the milk in a small saucepan until it is just lukewarm, about 110 degrees. Pour the milk into the bowl of an electric mixer and whisk in the yeast. Whisk in the butter, sugar, salt, egg yolks, and vanilla. Use a large rubber spatula to stir in about half the flour.
Place the bowl on the mixer and use the paddle attachment to beat the dough on low speed. Add the remaining flour about 1/2 cup at a time, beating to incorporate between additions. When all the flour has been added, beat the dough for 2 minutes. Stop the mixer and allow the dough to rest for 10 minutes. Beat the dough on low to medium speed for 2 minutes more.
Scrape the dough to a buttered bowl and turn it over so that the top is buttered. Cover the bowl with plastic wrap and chill the dough for 1 1/2 hours.
While the dough is chilling, prepare the filling. In a food processor fitted with the metal blade, combine the chocolate with the sugar, cocoa, and cinnamon, and pulse to grind finely. Pour the filling into a bowl and set aside.
After the dough has chilled, scrape it to a floured work surface and press it out to a rectangle about 10 x 15 inches. Evenly scatter the chocolate filling on the dough. Scatter the chopped walnuts over the filling. Roll up the dough from one long side jellyroll style and pinch the ends to seal. Use a knife to cut the roll into two equal pieces.
Invert one of the rolled pieces of dough, seam side down, into one of the prepared pans. Repeat with the remaining piece of dough. Cover the pans with dish towels or buttered plastic wrap and let them rise until doubled, 1 to 2 hours, depending on the temperature of the room.
About 20 minutes before the babkas are completely risen, set a rack in the middle level of the oven and preheat to 350 degrees.
Bake the babkas until they are well risen and deep golden, about 45 minutes.
Cool the babkas in the pans on a rack for 10 minutes, then unmold and cool them on their sides to prevent them from collapsing.