Mix the flour and salt. Make a mound with the flour with a dent in the middle, add the egg and butter to the dent, and gradually incorporate the flour into the liquid mixture. Add the warm water a tablespoon at a time until you have a pliable, silky dough. Let this dough rest in a warm spot for half an hour to one hour. Then roll it out on a floured kitchen towel.
Note: For an apple strudel this dough was a little bland and hard (sugar and more butter?). But it would probably make a great ravioli dough since it rolls out into a big thin sheet easily.