Chocolate Babka

Ingredients

• 1.3 cups bread flour 
• 1 tablespoon butter softened
• 5 tablespoons butter softened cut into pieces and
• 2.3 teaspoons yeast dry
• 1 large egg yolk lightly beaten
• 1 tablespoon flour all-purpose
• 1.7 cups flour all-purpose divided
• 0.5 cup granulated sugar 
• 1 teaspoon granulated sugar 
• 6 tablespoons granulated sugar 
• 0.5 teaspoon ground cinnamon 
• 0.8 cup warm milk 1% low-fat (105° to 110°)
• 2 tablespoons powdered sugar 
• 0.3 teaspoon salt 
• 4 ounces bittersweet chocolate finely chopped
• 3 tablespoons cocoa unsweetened
• 0.5 teaspoon vanilla extract 

Equipment

• bowl
• frying pan
• baking paper
• oven
• knife
• wire rack
• loaf pan
• stand mixer
• measuring cup

Directions

1. Dissolve 1 teaspoon granulated sugar and yeast in warm milk in the bowl of a stand mixer; let stand 5 minutes. Stir in 6 tablespoons granulated sugar, vanilla extract, 1/4 teaspoon salt, and egg yolk. Weigh or lightly spoon flours into dry measuring cups; level with a knife.
2. Add 6 ounces (about 1 1/3 cups) all-purpose flour and bread flour to milk mixture; beat with dough hook attachment at medium speed until well blended (about 2 minutes).
3. Add 5 tablespoons butter, beating until well blended. Scrape dough out onto a floured surface (dough will be very sticky). Knead until smooth and elastic (about 10 minutes); add 5 ounces (about 1/3 cup) all-purpose flour, 1 tablespoon at a time, to prevent dough from sticking to hands (dough will be very soft).
4. Place dough in a large bowl coated with cooking spray, turning to coat top. Cover and let rise in a warm place (85), free from drafts, 1 1/2 hours or until doubled in size. (Gently press two fingers into dough. If indentation remains, dough has risen enough.) Punch dough down; cover and let dough rest 5 minutes.
5. Line the bottom of a 9 x 5inch loaf pan with parchment paper; coat sides of pan with cooking spray.
6. To prepare filling, combine 1/2 cup granulated sugar, cocoa, cinnamon, salt, and chocolate in a medium bowl; set aside.
7. Place dough on a generously floured surface; roll dough out into a 16-inch square.
8. Sprinkle filling over dough, leaving a 1/4-inch border around edges.
9. Roll up dough tightly, jelly-roll fashion; pinch seam and ends to seal. Holding dough by ends, twist dough 4 times as if wringing out a towel. Fit dough into prepared pan. Cover and let rise 45 minutes or until doubled in size.
10. Preheat oven to 35
11. To prepare streusel, combine powdered sugar, 1 tablespoon all-purpose flour, and 1 tablespoon softened butter, stirring with a fork until mixture is crumbly; sprinkle streusel evenly over dough.
12. Bake at 350 for 40 minutes or until loaf is browned on bottom and sounds hollow when tapped. Cool bread in pan 10 minutes on a wire rack; remove from pan. Cool bread completely on wire rack before slicing.