As a follow-up question, I keep following the recipe to the letter and thank goodness I get pillowy and soft buns each and every time. The thing that bothered me a bit was the smell of the egg-wash when the buns are still hot.
I read here that you can use anything as a glaze, milk or even water, so I decided to brush the buns with milk (plus a pinch of saffron for extra bonus!), and sadly I ended up with buns that developed a crust and were not as soft as the previous batches.
I wonder if the egg-wash plays a role as important as making the buns soft and shiny, painting the buns with milk was the reason behind the crust? So only egg-wash makes the buns soft?