If you are using dry active yeast, you need to activate by adding 1/2 cup of lukewarm water and set aside for 5 minutes or when bubbles form. If you are using instant yeast you can directly add to dry ingredients.
In a mixing bowl put bread flour, powdered milk, sugar and mix well together. (if you are using instant yeast, you can add it with the rest of the dry ingredients).
When the yeast mixture is activated (bubbles forming on top of mixture), add the egg and pour in with the dry ingredients.
Using a stand mixer with the hook attachment, mix everything in low speed until well incorporated.
Then add butter and salt and continue beating in low speed for 5 mins. When the butter mixed well with the dough continue beating in medium speed until your dough becomes soft and elastic.
Removed dough from mixing bowl then place it in another bowl greased with cooking oil and let it rise for 1 hour or depending on the humidity.
When the dough doubled in size you know you achieved a good rise. Dump the dough on the table or counter and punch the dough to release the air/gas inside.
Divide the dough in two equal parts. Set aside one part and cover with dry kitchen towel.
With the other dough, Flatten with a rolling pin and roll into a log shape and cut into small equal pieces (40 grams of dough) or approx. the size of a medium tomato.
Take one piece from the that you just cut and roll it into a shape of an elongated ball. Do this procedure to the dough you set aside.
Place all the dough on a baking tray with parchment paper and let it rise for 20 minutes. While waiting you can pre-heat the oven (375°F or 180°C°).
Before baking apply eggwash (1 beaten egg + 1 tbsp milk) and poke the top of dough with fork.
Bake for 15 to 20 minutes depending on what oven you are using or until golden brown. then let cool down