Mix the milk and water in a mixing bowl so that the liquid is lukewarm.
Add the yeast, sugar, flour, salt and oil and knead until combined.
Add the butter in pieces and knead for another 8 minutes. (If the dough is too sticky, add another spoonful of flour. The dough should be soft).
Flour the work surface slightly, so the dough does not stick and form into a ball.
Lightly oil the bowl, put the dough back in and cover.
Leave to rise in a warm place for about 1 hour.
Place the dough on a lightly floured work surface and divide into 10 pieces. (Of course, you can make more or less depending on how big you want the buns to be).
Shape it into balls.
Place on a baking tray with baking paper and flatten with your hands.
Leave to rise again for about 30 minutes.
Brush the buns with a mixture of yolk and milk.
Sprinkle with sesame seeds.
Bake in preheated oven at 200°C for about 15 minutes (with steam).
When the buns are baked, cover with a clean tea towel for about 10 minutes.
Fill or garnish as desired and enjoy.