For the grape strudel, roast the hazelnuts and pumpkin seeds in butter and deglaze with rum. Peel the apple and roughly slice or grate.
Cut the grapes in the middle and remove the seeds if necessary. Mix apples and grapes, add some rum and sugar.
Place the puff pastry on a damp cloth and spread the hazelnut/pumpkin seed mixture first. Then apply the fruit mixture.
Roll up the strudel and brush with a little melted butter. Bake in the oven at about 200 degrees for 30 minutes.
Sprinkle the grape strudel with powdered sugar.