Put 300ml milk and a cinnamon stick in a small saucepan. Bring to a steady simmer, then remove from the heat. Add 50g butter and stir, then cover and leave to infuse until the milk is warm but not hot.
Mix together the flour, yeast and caster sugar in the bowl of a stand mixer. Make a well in the middle of the dry ingredients and add the egg, then strain in the milk. Using the dough hook attachment, mix the ingredients on low until it comes together, periodically using a spatula to scrape the sides of the bowl. Adjust to a medium-high speed and mix for 3-4 minutes until the dough is still soft and slightly sticky but coming away easily from the sides of the bowl.
Lightly grease a large bowl and scrape the dough into it. Cover with greased clingfilm and then leave in a draught-free warm place for 45 minutes. Once the dough has doubled in size, dust your kitchen surface with flour. Lightly punch down the dough and tip out on to the floured surface. Roll out into a rectangle shape approx 25 x 40cm.
Empty the Lotus spread into a small bowl and warm in a microwave in 10-second bursts until softened, but not runny. Using an off-set spatula, spread it evenly across the dough, leaving a 1cm border all around. Starting with the longest side, roll the dough up as tightly as possible (it’s a very soft dough, so be gentle with it) until you have a long Swiss roll-like shape. Use a little water to help seal, keeping the sealed edge at the bottom.
Cut the length of dough into 12 equal pieces. Fit the pieces into a rectangular 24 x 30cm greased baking dish, cover with greased clingfilm, and leave in a warm place for 30 minutes until the buns have increased in size. At this stage, preheat your oven to 205°C/gas mark 5. Transfer to the oven and bake for 25-30 minutes until the buns are nicely browned.
While the buns bake, heat the remaining 15g butter in a small saucepan over a low heat for 3-4 minutes until melted and starting to brown, giving off a toasty smell. Remove from the heat and stir in the Lotus biscuit crumbs until combined. Stir in the demerara sugar then spread the mixture out on a small plate. Transfer to a fridge to chill.
Once the buns have baked, leave them to cool in the dish for 20-25 minutes until no longer hot but still warm. While they cool, whisk together the icing sugar, 1 tbsp of milk and ground cinnamon until smooth. Beat the cream cheese and then add to the icing, beating together until smooth and runny. Use the back of a spoon to drizzle the cream cheese glaze over each bun. Leave to sink in for 5 minutes and then scatter over the biscuits crumbs. Serve.