Chocolate Banana Bread Babka

Ingredients

• Dough
• ⅔ cup (127g) whole milk
• 2⅔ cups (316g) all-purpose flour
• ¾ cup (85g) whole-wheat flour
• ⅓ cup (71g) light brown sugar
• 2 teaspoons instant yeast
• ½ teaspoon fine sea salt
• ½ teaspoon ground cinnamon
• 2 medium (240g) ripe bananas, mashed
• 1 large (57g) egg
• 1 large (22g) egg yolk
• Filling
• ½ cup (115g) heavy cream
• 6 tablespoons (85g) unsalted butter
• ½ cup (106g) light brown sugar
• 5 ounces (142g) bittersweet chocolate, finely chopped
• 1½ teaspoons pure vanilla extract
• Streusel
• ½ cup (60g) all-purpose flour
• ¼ cup (53g) light brown sugar
• 2 tablespoons (11g) cocoa powder
• 5 tablespoons (71g) unsalted butter, melted
• 1 medium (120g) ripe banana, finely chopped