Chocolate Cinnamon Babka

Ingredients

• 1 cup warm tap water (110-115°F)
• 1 tablespoon Red Star Quick Rise Yeast
• 3 tablespoons granulated sugar
• 1/3 cup dried milk powder
• 1 large egg
• 3 1/2 cups all-purpose flour (plus extra for dusting your worktop)
• 4 tablespoons olive oil, divided
• 1/2 teaspoon table salt
• 4 tablespoons (1/2 stick) unsalted butter
• 2 tablespoons cocoa powder
• 2 tablespoons granulated sugar
• 6 ounces dark chocolate chips
• 1 1/2 tablespoons ground cinnamon
• 1/4 cup all-purpose flour
• 1 tablespoon ground cinnamon
• 2 tablespoons unsalted butter
• Egg wash: 1 egg + 1 teaspoon water (beaten together)