Prepare the dough

1. Place the flour, caster sugar, salt, yeast and milk powder in the mixer bowl of a stand mixer. Mix well and create a well in the centre. Pour in the warm milk.
2. Start kneading the dough with a dough hook attachment at medium speed for about 5 minutes.
3. When the dough comes together, add in the softened butter, a little at a time.
4. Continue to knead the dough for a further 3 to 5 minutes or until it passes the windowpane test. This involves taking a small piece of dough and gently stretching it until it is thin enough to see light through it, without it tearing.
5. Transfer the dough to an oiled bowl and cover it with cling film. Place it in a warm place for the first proof until it doubles in size. It should take between 1 to 2 hours.
6. Remove the cling film, sprinkle some flour on top of the proofed dough. Knock out the air and transfer it to a lightly flour-dusted surface. Knead the dough for around 3 minutes.
7. Divide the dough into 6 equal pieces using a kitchen scale, around 68g each.
8. Shape each dough into a ball and place it on a lined baking pan, 2” apart.
9. Cover with a tea towel and rest for 10 minutes.
10. Flatten one piece at a time on a work surface. Take a frozen butter cube and carefully wrap it with the dough, making a little parcel. Pinch the ends tightly to avoid butter leaking out during baking. Repeat the same process for the other 5 pieces.
11. Cover with a tea towel for the second proof until they almost double in size. This may take between 30 minutes and 2 hours (the frozen butter can slow down the process but be patient!).

Prepare and apply the coffee topping

1. Meanwhile, preheat the oven to 180°C/355°F.
2. Dissolve the coffee in the hot water. Set aside to cool down.
3. Whisk the egg. Set it aside.
4. Cream the butter and the sugar in a mixing bowl, start with a spatula, then mix with a hand held mixer until pale and fluffy.
5. Continue to mix and add in the beaten egg, little by little, until they are well combined.
6. Add in the cooled coffee mixture and continue to mix.
7. Sift in the flour and fold into the mixture (start with a spatula to prevent the flour flying up).
8. Continue to mix until everything is well mixed.
9. Transfer the batter into a piping bag and secure with a rubber band or clip. If you’re not ready to use it, place the bag in the fridge until needed.
10. Uncover the proofed buns. Cut a hole at the top of the piping bag and pipe swirls of the coffee topping over the top of the buns until it covers around half of the buns (don’t worry about neatness, the swirls will smooth together during cooking – but try not to leave gaps).
11. Then bake the buns for 15 minutes, or until cooked through.
12. Remove from the oven and cool for 5 minutes before transferring onto a wire rack.
13. Enjoy while still warm – absolutely delicious!