How to cook
Mix the flour, sugar, salt, powdered dry milk, dry yeast and vanilla together. Top up with hot water and the beaten egg. Allow the mixture to activate for 15 minutes under a lid. Then add the butter and mix well.
By adding flour, knead a smooth and non-sticky dough. Leave the dough at room temperature to rise for about 45 minutes. Then spread it onto a greased surface into a crust with a thickness of 1/2″ (1 cm). With a glass, cut out donuts and make a small round hole in the middle. Leave them on the counter to rise for another 45 minutes.
Preheat oil in a deep skillet over low heat and drop the donuts to fry on both sides. When ready, drain on a paper towel, then cover them with the desired frosting or powdered sugar.