Mix the rhubarb with granulated sugar and let stand for about 1/4 hour. (The rhubarb leaves water when marinating).
Preheat the oven to 200 °C. Prepare the pastry sheets according to the package instructions.
Heat some butter, fry breadcrumbs in it until golden brown. Mix with grated almonds, vanilla sugar, powdered sugar, cinnamon and lemon zest.
Spread out the pastry sheets and sprinkle with the breadcrumb mixture. Place 3 rhubarb stalks on each dough sheet, fold the dough in at the sides and roll into small strudels.
Place these on a baking sheet lined with baking paper and brush with melted butter.
Bake in the preheated oven on the middle shelf for about 10 minutes.