Put the flour on a pastry board and make a well in the centre. In this, put the egg, the oil and a pinch of salt. Mix first with a knife, then knead with the hands, adding a little water gradually. Work for 15 to 20 minutes, taking the dough in the hands and beating on the board. When it shows bubbles and no longer adheres to the hands, put it on a floured board, cover with a basin and let it stand for 1 hour. Put a large clean cloth on the kitchen table, sprinkle it with flour and roll out the dough. Lift the dough and, with the back of the hands under it, pull and stretch it carefully until it reaches the size of the cloth and is very thin and transparent. This is not an easy thing to do, and practice and experience are required to do this pulling without breaking the very thin paste. Lay the paste on the cloth and carefully trim off the pieces hanging over the side of the table. Now brush the paste over with melted butter, sprinkle with the fried breadcrumbs, the sliced apples, the raisins, currants and sugar. Lift the two corners of the cloth with both hands and roll the paste into a long thin sausage. Bend it and place carefully on a well-greased tin, brush over with melted butter or fat, and bake till it is a nice golden colour. Sprinkle with sugar, cut in thick slices and serve hot. There are many different varieties of strudel fillings. It can be filled with different kinds of fruit or with sour milk or cream mixed with yolks of eggs, sugar, raisins and currants.