Step 2

Make the filling: In a medium saucepan, whisk together the eggnog and cinnamon. Bring to a simmer over medium heat, then cook until thickened, 20 to 22 minutes. Remove from the heat and stir in 1 cup of the white chocolate until the chocolate is melted and incorporated. Let cool completely. Roughly chop the remaining 1 cup of white chocolate and set aside.

Step 3

Make the dough: In a large bowl, combine the eggnog and yeast. Let sit until it begins to foam, about 10 minutes. Meanwhile, in a medium bowl, whisk together the flour, salt and cinnamon, and set aside.

Step 4

To the foamy yeast mixture, add the granulated sugar and 3 eggs, and whisk to combine. Slowly stir in the flour until a dough forms, then transfer to a lightly floured surface. Using your hands, knead in the softened butter, a little at a time, until a smooth dough forms. Place in a greased bowl and cover with plastic wrap. Let rise in a warm place until doubled in size, about 1 hour.

Step 5

Meanwhile, make the glaze: In a small saucepan, combine the brandy and sugar. Bring to a simmer and cook until the sugar dissolves, 2 minutes. Remove from the heat and let cool.

Step 6

Assemble the babka: Preheat the oven to 350° and grease two 9-by-5-inch loaf pans. Divide the dough into 2 balls. On a lightly floured surface, roll 1 ball of dough out into a 14-inch square, about ⅛ inch thick.

Step 7

Spread half of the filling evenly over the surface of the dough, leaving a 1-inch margin at the top of the square. Sprinkle half of the chopped chocolate over the filling. Starting with the edge closest to you, roll the dough up tightly. Leaving ½ inch of dough intact, cut the roll lengthwise into two strands. Twist the strands together and pinch at the end to seal. Carefully place the babka in one of the prepared pans.

Step 8

Repeat this process with the remaining dough and filling. Cover both babkas loosely with plastic wrap and place in a warm area until the dough expands to fill the pan, 45 minutes more.

Step 9

In a small bowl, beat the remaining egg and liberally brush onto each babka. Bake, rotating halfway through, until golden and cooked through, 40 to 45 minutes. As soon as the babkas come out of the oven, brush the tops with the brandy syrup to coat.

Step 10

Let cool slightly, then remove each bread from the pan and let cool completely before slicing and serving.