Chocolate Tahini Challah Buns

Make dough: Whisk eggs, yolk, sugar, oil and milk or water in the bottom of a stand mixer bowl. Add flour, yeast, and salt and combine with dough hook until it comes together, then let machine knead it for 5 to 7 minutes. Oil a large bowl and let dough rise in it at room temperature for 2 to 2 1/2 hours, until slightly shy of doubled. If ingredients are cold, it might take 30 to 45 minutes longer. Speed up rising by placing dough in a warm (150°F) oven, watching closely as it rises quickly. Butter a 9×13-inch baking dish or coat it with nonstick spray.

Make filling: Melt butter and chocolate together until smooth. Stir in powdered sugar, cocoa, and tahini; mixture should be a spreadable consistency. If filling is thin, chill it briefly to thicken.

Assemble buns: Roll out dough on a floured surface into an 18-inch wide rectangle. Spread chocolate mixture over dough and roll tightly. Cut log into 1 1/2-inch to 2-inch segments and arrange in prepared pan. Beat egg and brush tops of buns, cover with plastic wrap, and let proof for 60 to 90 minutes (or refrigerate overnight).

Bake buns: Remove buns from fridge to warm up for 30 minutes. Heat oven to 350°F. Brush tops with egg wash again, sprinkle with sesame seeds, and bake for 30 minutes, until bronzed with an internal temperature of 190°F. Let cool slightly before serving.

To glaze (optional): Whisk powdered sugar with lemon or orange juice until smooth. Drizzle over cooled buns or serve alongside.