In a large measuring jug, combine the warm milk, granulated sugar, and active dry yeast. Stir gently, then leave for about 10 minutes, until the mixture becomes foamy and bubbly.

Pour the yeast mixture into a large mixing bowl. Add the melted butter, eggs, and egg yolk, and whisk until combined.

Add the bread flour, cocoa powder, and salt. Mix until a soft, sticky dough forms.

Transfer the dough to a lightly floured surface and knead for about 5 minutes, until smooth, elastic, and slightly tacky. The dough should feel soft and may stick briefly to your hands, but should pull away cleanly.

Place the dough in a lightly greased large bowl and cover with clingfilm or a clean tea towel. Leave to rise in a warm place for 1–2 hours, or until doubled in size.

In a medium mixing bowl, stir together the partially melted butter, light brown sugar, and ground cinnamon until well combined. Set aside.

Once the dough has doubled in size, gently punch it down to release the air. Transfer it to a lightly floured surface.

Roll the dough into a large rectangle, approximately 30 × 46cm (12 × 18 inches) and about 6mm (¼-inch) thick, with one of the longer sides facing you. Trim the edges if necessary to create a neat rectangle.

Spread the cinnamon sugar filling evenly over the dough, leaving a small border around the edges. Sprinkle the chocolate chips evenly over the filling.

Using a pizza cutter or sharp knife, cut the dough into 12 equal strips, each approximately 3.8cm (1½ inches) wide. Roll up each strip tightly and arrange the rolls in a lightly greased 23 × 33cm (9 × 13-inch) baking dish.

Cover the dish loosely with clingfilm or a clean tea towel and leave the rolls to rise in a warm place for another 30 minutes, until noticeably puffed up.

Meanwhile, preheat the oven to 180°C/160°C Fan/350°F/Gas 4.

Remove the covering and bake for 30–35 minutes, or until the rolls are set and the centres reach an internal temperature of 88–93°C (190–200°F).

Place the baking dish on a wire rack and allow the rolls to cool slightly while preparing the icing.

In a medium mixing bowl, beat together the softened cream cheese and melted butter until smooth and combined.

Add the icing sugar, cocoa powder, and vanilla extract. Mix until smooth, creamy, and fully incorporated.

Spread the icing evenly over the warm cinnamon rolls. Serve and enjoy!