Break egg into measuring cup. Add enough water to make 1/3 cup; mix.
Combine salt, 1 tablespoon butter and sugar; stir in egg mixture.
Add 3/4 cup flour; mix to form soft dough.
Sprinkle remaining flour on pastry cloth. Turn out dough; knead lightly with fingertips until flour is absorbed.
Brush with 1 teaspoon oil. Cover with warm bowl and let stand 2 to 4 hours.
Pat into flat circle; roll into 12" circle. Brush top with remaining oil. Using back of hand, stretch dough from middle until it is as thin as tissue paper.
In a large bowl, mix together all filling ingredients. Spread filling over dough to 1" from edge. Roll like jelly roll; seal edge.
Place on cookie sheet, seam side down. Brush top with remaining butter.
Bake in preheated 400° oven for 20-25 minutes.
Cool and sprinkle with powdered sugar.