Heat the milk until lukewarm, then add the sugar and yeast. Leave to the side for 5 minutes.
Add the flour and salt to a mixing bowl, then combine with the milk mixture, kneading for ten minutes by hand or five minutes with a stand mixer on low.
Add the room temperature butter and knead to combine. If the dough is too sticky, add small increments of flour until workable.
Cover the dough with a tea towel and leave to prove for at least 1.5 hours, or until it has doubled in size.
Roll out the dough into a rectangle measuring 40cm by 45cm.
Gently heat the Hot Cross Bun Caramel in the microwave for 10 seconds and spread evenly over the dough.
Roll the dough tightly along the 45cm edge to form a spiral, then cut into 10cm wide rolls.
Place the rolls in a baking tray, evenly spaced, and leave to prove for another 30 minutes or until the rolls are touching.
Bake in the oven at 190°C for 20–25 minutes or until golden brown.
Mix together the butter, icing sugar, and vanilla essence to make the icing.
Once the rolls are nearly cooled, pipe icing crosses on each bun, dust with ground cinnamon, and top with crushed Cinnamon Roll Popcorn.