Activate the Yeast: In a large mixing bowl, combine the warm milk, yeast, and 25g of the granulated sugar. Give it a gentle stir. The mixture should smell subtly yeasty and begin to foam and bubble within 5-10 minutes, indicating the yeast is active and ready. If it doesn't foam, your milk might have been too hot or too cold, or your yeast is past its best, and it's best to start again.

Prepare the Dough: Add the melted butter, egg, remaining 50g granulated sugar, and salt to the yeast mixture. Stir until well combined. Gradually add the strong white bread flour, mixing with a wooden spoon until a shaggy dough forms. Once it comes together, turn it out onto a lightly floured surface.

Knead the Dough: Knead the dough for 8-10 minutes. At first, it will feel a little sticky, but as you knead, it will become smooth, elastic, and springy to the touch. You'll notice it changing from a rough, floury lump to a soft, pliable ball that holds its shape and springs back when gently poked. Place the dough into a lightly greased bowl, turn it once to coat, and cover with cling film. Let it rise in a warm place for 1-1.5 hours, or until it has visibly doubled in size and feels airy.

Form the Rolls: Once risen, gently punch down the dough to release the air. Turn it out onto a lightly floured surface and roll it into a large rectangle, approximately 30x40cm. In a small bowl, mix the cinnamon and light brown sugar. Brush the entire surface of the dough with a thin layer of melted butter (about 1 tablespoon), then evenly sprinkle the cinnamon-sugar mixture over it, leaving a small border along one long edge. Finally, scatter the chocolate chips generously over the cinnamon-sugar.

Roll and Slice: Starting from one of the long edges, carefully roll the dough into a tight log. Pinch the seam gently to seal it. Using a sharp, un-serrated knife or a piece of dental floss, slice the log into 12 even rolls, each about 3-4cm thick. As you slice, you'll see the beautiful swirls of cinnamon and chocolate emerge. Arrange the rolls snugly in a lightly greased 23x33cm baking dish.

Second Rise and Bake: Cover the baking dish loosely with cling film and let the rolls rise again in a warm spot for another 30-45 minutes, or until they look puffy and have nearly doubled in size. While they rise, preheat your oven to 180°C (160°C fan/Gas Mark 4). Once risen, bake for 20-25 minutes. The rolls should turn a beautiful golden-brown on top, and you’ll notice a wonderful sweet, spicy, and chocolatey aroma filling your kitchen. The centres should feel soft and slightly springy when gently pressed.

Prepare the Icing: While the rolls are baking, whisk together the icing sugar, 2 tablespoons of milk, and vanilla extract in a small bowl until smooth. If it's too thick, add the remaining tablespoon of milk, a tiny drop at a time, until you reach a pourable yet thick consistency. The icing should be bright white and glossy.

Ice and Serve: As soon as the rolls come out of the oven, while they are still warm and steaming, generously drizzle the prepared icing over them. The warmth of the rolls will make the icing melt slightly and seep into all the crevices, creating a beautiful glaze. Serve immediately and enjoy the pillow-soft texture and comforting warmth.