• In a bowl of a stand mixer fitted with a dough hook, add the yeast, milk, and one tablespoon of sugar. Let it sit for 5 minutes and become foamy.
• Add the remaining sugar, flour, cocoa powder, cinnamon, orange zest, vanilla, salt, and egg. Turn the mixer on medium and combine until it forms a thick but slightly sticky dough. Add in the room temperature butter and keep mixing until the butter has been incorporated.
• Keep it mixing until the sticky dough strengthens, comes together, and pulls away cleanly from the sides of the bowl. This can take around 15 minutes. Proper gluten development will allow you to stretch the dough so thin you can almost see through it.
• Pull the dough out of the bowl onto a clean workbench and flatten it. Add in the chocolate chips and gently work them into the dough.
• Form the dough into a ball. Place the dough ball into a clean bowl, cover it with a lid or plate or a damp tea towel, and let it in a warm spot for 1.5- 2 hours until doubled in size. If making overnight orange chocolate hot cross buns, the dough can be covered tightly with plastic wrap and placed in the refrigerator overnight to rise slowly.

Kneading by hand

• Add the yeast, milk, and one tablespoon of sugar to a large bowl. Let it sit for 5 minutes and become foamy. Add the remaining dough ingredients except for the butter and chocolate chips and mix with a fork until it makes a shaggy dough. Tip it out onto a clean bench to knead it further, then work in the room temperature butter, a cube at a time.
• For a wet dough like this, using a slap and fold method is easiest - slap the dough down hard on the bench, pull it forward quickly, and repeat. Quick motions can stop the dough from sticking to your hands too much. It will be very sticky but do not be tempted to add more flour. After a while, you will start to feel strength gathered in the dough.
• It can be tiring, so you can take breaks in between kneading the dough will respond well to it. Come back to it with clean and slightly damp hands. Once kneaded, gently work in the chocolate chips.
  
• Form the dough into a ball. Place the dough ball into a clean bowl, cover it with a lid or plate or a damp tea towel, and let it in a warm spot for 1.5- 2 hours until doubled in size.

Shaping 

• After the dough has been proofed, it’s then time to shape the dough. If your dough was in the fridge overnight, it would be pretty firm. You can let it come to room temperature for 20 minutes before shaping.
• Pull the dough onto a clean bench and cut it into nine even pieces. You can use a scale for exact measurements. Use your hands to form each piece into a tight ball. 
• Line a 10x10 inch square baking dish with parchment paper. Place each ball into the baking tray, then cover with a damp tea towel and let them rise until doubled in size.

Baking

• Preheat the oven to 350 F/ 180 C.
• Mix the flour, cocoa powder, sugar, and water for the crosses, then pipe the crosses onto the buns using a piping bag fitted with a small round tip. Bake the buns for around 25-28 minutes.

The glaze

• In a saucepan, combine orange juice with granulated sugar. Bring the mixture to a simmer and stir until the sugar has dissolved. Once dissolved, remove the heat and brush it over the buns as they come from the oven.