Knead the water, flour, egg, salt and melted butter into a smooth dough and let it rest for 1 hour with the lid closed.
In the meantime, finely chop the peppers, chop the onions and garlic. Heat the lard and sauté the chopped peppers and sauerkraut for about 10 minutes. Season, cool.
Roll out the dough on a floured kitchen towel and cover with slices of salami. Spread remaining ingredients evenly on dough and roll up carefully with kitchen towel. Place the strudel on a greased baking tray, brush with butter and bake for about 35 minutes at 220 degrees.