These sweet, soft and lightly spiced buns are delicious with a cup of tea. Made using the Asian baking technique known as ‘tangzhong’, they result in the lightest, softest dough.
For the tangzhong, whisk the flour with 150ml of water in a saucepan over a low heat until the mixture has thickened to a curd-like consistency (about 3 minutes). Remove from the heat and leave to cool.
Make the dough. Gently warm the milk to 46°C on the cooking thermometer, either in a microwave or in a small pan over a low heat. Remove from the heat and stir in the sugar and yeast. Set aside for 5 minutes, until the mixture is frothy.
Tip the flour and salt into a stand mixer fitted with the dough hook. Add the eggs, butter, condensed milk, yeast mixture and tangzhong, and mix on low speed to combine. Increase the speed to medium and knead for about 5 minutes, until you have a smooth and elastic dough.
Turn out the dough onto a lightly floured work surface and shape it into a neat ball. Place the dough in an oiled bowl, cover and leave to rise for about 1 hour, until doubled in size.
Meanwhile, make the cinnamon filling. Beat together the butter, sugar and cinnamon until smooth.
Turn out the risen dough onto the work surface and knead it for 30 seconds to knock out any large air pockets.
On a lightly floured surface, roll out the dough into a large rectangle about 1cm thick (aim for about twice as long as it is wide). Spread the cinnamon filling evenly over the dough using a palette knife or spoon. Turn the dough so that a long edge is closest to you. Starting from that long edge, roll up the dough into a long sausage, keeping the roll even and tight.
Trim the ends of the roll to neaten, then cut the roll along its length into 15 equal pieces. Turn the pieces cut-sides up to show the swirl and arrange them neatly in the prepared baking tray, in three rows of five.
Cover with a clean tea towel and leave the rolls to prove for 30–45 minutes, until they have almost doubled in size.
Heat the oven to 180°C/160°C fan/350°F/Gas 4. Make the egg wash by beating together the egg and milk. Brush this all over the buns. Bake the buns on the middle shelf for 20–25 minutes, until risen and golden.
While the buns are baking, prepare the icing. Combine the icing ingredients together in a bowl and beat well with a wooden spoon or electric hand mixer until smooth. Spoon the icing into the piping bag, if using, and set aside. (Alternatively, you can leave the icing in the bowl and use a spoon for drizzling in the next step.)
Once the cinnamon rolls are baked, remove them from the oven and leave them to cool in the tin for 5 minutes. Transfer the buns to a wire rack, snip the tip off the piping bag and generously drizzle the icing back and forth over the top (alternatively, use a spoon to drizzle). Gently separate the buns before serving.