For the sweet Grammelstrudel knead sugar, flour, baking powder, sour cream, 1 egg and 2 yolks to a soft strudel dough. Let the dough rest in a cool place for 1 hour, then roll it out, spread with jam and cover with grammel, roll it up and put it on a baking tray covered with baking paper.
Prick several times with a fork and brush with beaten egg. Bake the sweet grammel strudel on the middle rack, at medium heat for about 45-50 minutes.