Mix all the ingredients except butter and flour in a bowl. When mixed, add butter and flour and make a dough. Knead for 10 minutes (add more flour if it's too sticky).
Let the dough rise under a tea towel until it's doubled in size, about an hour. Divide into 8 pieces and roll into balls. Flatten the balls a fair bit and put on a baking tray. Let rise under a tea towel for another hour.
Brush the buns with eggwash and sprinkle some sesame seeds over them (optional). Bake in the oven at 200 degrees for 10-12 minutes, until nice and golden. Enjoy!
Note: this dough will also make lovely hot dog buns! Divide the dough into 12 pieces and roll into little sausages, sprinkle with some flour and rise for 45 minutes. Bake like burger buns.
