0.5cupunsalted butter, melted and cooled to room temperature
3largeeggs, at room temperature
1teaspoonvanilla extract
1cuphazelnuts, toasted and roughly chopped
1cupchocolate hazelnut spread (such as Nutella)
0.25cupunsweetened cocoa powder
1eggfor egg wash
Instructions
In a large mixing bowl, vigorously whisk together the flour, granulated sugar, active dry yeast, and salt until evenly combined. In a separate bowl, whisk together the warmed milk, melted butter, room temperature eggs, and vanilla extract until well blended. Gradually pour the wet mixture into the dry ingredients, stirring with a wooden spoon or spatula until a rough dough forms.
Transfer the dough onto a well-floured surface. Knead the dough for about 8-10 minutes, until it becomes smooth and elastic. Gather the dough into a ball and place it into a greased bowl, turning it to coat in the oil. Cover the bowl with a clean kitchen towel. Allow the dough to rise in a warm spot for 1-2 hours or until it has doubled in size.
In a medium bowl, mix the chocolate hazelnut spread and cocoa powder until creamy and uniform. For added texture, you may blend in half of the toasted hazelnuts into the filling, if desired.
Once the dough has risen, punch it down to release excess air. On a floured surface, roll the dough into a rectangle about 16x24 inches. Evenly spread the chocolate hazelnut filling across the entire surface. Sprinkle the remaining chopped hazelnuts over the filling.
Starting from one long edge, tightly roll the dough into a log, sealing the seam by pinching it closed. Using a sharp knife, carefully slice the log in half lengthwise to reveal the luscious chocolate filling inside. Twist the two halves together with the filling facing up. Coil the twisted dough into a spiral shape and transfer it into a greased 9x5 inch loaf pan.
Cover the loaf pan with a towel and let the babka rise for an additional 30-45 minutes, until it appears puffy and has expanded.
During the last 10 minutes of the rising period, preheat your oven to 350°F (175°C).
In a small bowl, beat the extra egg for the egg wash. Brush the top of the risen babka generously with the egg wash to create a beautifully glossy finish.
Place the babka in the preheated oven and bake for 30-35 minutes, or until it is deep golden brown and sounds hollow when tapped. If the top browns too quickly, loosely cover it with aluminum foil halfway through the baking process.
Remove the babka from the oven and let it cool in the pan for about 10 minutes. Then, transfer it to a wire rack to cool completely. Once slightly cooled, slice the babka into generous pieces and serve warm or at room temperature for delightful enjoyment.
Notes
Serve on a wooden cutting board, dusted with powdered sugar and paired with fresh berries or whipped cream.