MAKE DOUGH: Add all dough ingredients (in the order listed) into the bread machine pan. Select DOUGH cycle and start.

CHECK DOUGH: After 1 minute, make sure paddles are engaged. At 15 minutes, adjust with flour or liquid so dough sticks to sides, then pulls away cleanly.

CHILL DOUGH: When cycle ends and dough has doubled, remove, compress by hand, and chill in a greased bowl for 30 minutes or overnight.

MAKE FILLING: Place unsalted butter and bittersweet or semi-sweet chocolate in a microwave-safe bowl. Microwave on 50% power for 2 minutes until completely melted. Stir until smooth. Add powdered sugar, Dutch-process cocoa, and cinnamon to the melted mixture. Stir until smooth. Set aside to cool.

GLAZE: Combine egg, water, and a pinch of table salt in a small bowl. Whisk until smooth. Set aside.

SUGAR SYRUP: Combine granulated sugar and water in a small microwave-safe bowl. Don't stir. Microwave on HIGH for 2 minutes or until the sugar is dissolved. Set aside.

ROLL DOUGH: Roll chilled dough to about 26×16 inches. Spread filling to edges, leaving ¼" at the short end farthest from you.

SHAPE LOAF: Roll tightly starting from the short end closest to you, pinch seam, and freeze log for 10 minutes. Slice lengthwise, twist halves cut-side up, and tuck ends. Place in a greased loaf pan.

BAKING: Preheat your oven to 350 °F (180˚C). Brush the loaf with egg glaze. Bake for 40-45 minutes, or until the internal temperature of the bread reaches 190-195 °F.

FINISH: Brush with sugar syrup immediately after removing the bread from the oven. Let it stand in the pan for 30 minutes and transfer to a cooling rack for another hour before slicing.