To make the tangzhong, place the flour in a saucepan and gradually whisk in the milk to avoid lumps
Place the pan over a medium/low heat and whisk constantly until the mixture has thickened to a paste/pudding-like consistency.
Scrape the tangzhong into the bowl of a stand mixer fitted with a dough hook and add the cold milk, the pumpkin puree and the sugar. Stir to combine; it doesn't matter if it is a bit lumpy, you are just cooling the tangzhong down so that it doesn't kill the yeast.
Add the flour, yeast, pumpkin spice and salt. Don't let the salt touch the yeast. With the mixer on a low speed, mix for about 4 minutes until it forms a rough dough. Increase the speed to medium and mix until it is smooth and stretchy.
Add the butter and continue to mix on a medium speed until the butter is fully incorporated, the dough is smooth, elastic and no longer feels greasy and it is pulling away from the sides of the bowl cleanly.
Place the dough in a lightly oiled bowl, cover and set aside to rise in a warm spot until doubled in size, about 1 ½ - 2 hours.
Punch down the risen dough and add the chocolate chips. Knead until they are evenly combined.
Divide the dough into 12 even pieces (use a scale for accuracy).
Shape each piece into a ball by gathering the edges up and pinching them together. Keep going until you have a neat, well-sealed ball. Try and make sure that the chocolate chips aren't on the surface of the ball, otherwise they may burn in the oven.
Flip the ball over, cup it with your hand over the top and roll it until it is smooth.
Arrange the balls in a lined approx 20 x 30 cm tin. Loosely cover and set aside to rise until puffy, about 45-75 minutes. If you gently press the dough with your finger it should spring back slowly, and maybe leave a slight indentation. If it springs back quickly then it needs a little longer, and if the dough deflates then it is over-prooved so keep an eye on it!
When the bread is nearly ready, preheat the oven to 180°C/160°C fan/350°F/gas mark 4. Mix the milk and maple syrup together in a small bowl.
Gently brush the rolls with the milk mixture, then bake for 25-30 minutes. They should be deep golden and a probe thermometer inserted into the centre should reach at least 90°C/194°F.*
Allow to cool in the tin for 10 minutes then carefully lift them out onto a wire rack and leave to cool for about 30 minutes before serving.