In a large bowl of a stand mixer, add the flour, yeast, sugar, salt and orange zest. Use the paddle attachment to mix on low speed for about one minute.

Add the egg and egg yolk then slowly drizzle in the water. Once you have a hydrated shaggy mass, replace the paddle attachment with the dough hook.

Knead the dough on medium speed for about 2-3 minutes.

Add the butter, increase speed to medium-high and knead for another 5-7 minutes, until you have a smooth dough that stretches easily without tearing.

Spray the dough with oil spray, cover it with plastic wrap and set at a warm spot for 90-120 minutes. Make the filling during this time.

To make the filling, place the butter, powdered sugar and cocoa powder in a large bowl and mix until you have a smooth paste.

Divide the dough into parts.

Over a lightly floured surface, roll each part into a 12x10-inch rectangle.

Spread half the amount of chocolate filling, and sprinkle ½ cup of mini chocolate chips.

Roll the dough from the top part towards you and place each log over a large baking sheet lined with parchment paper.

Brush the logs with an egg wash and sprinkle with sesame seeds. Set aside to proof for another 90-120 minutes.

Bake at 350°F (180°C) for 25 minutes turning the pan at the 15 minute point.

Remove from the oven, and allow to cool before slicing.