Roast the chopped onion and the finely chopped peppers in a little oil. Add the minced meat, season with salt and pepper and fry until crumbly. Let cool and mix with the ketchup. In the meantime, preheat the oven to 220 °.
Spread the cooled mixture on the puff pastry, spread the cheese on top, sprinkle with oregano and paprika. Fold up and brush the strudel with beaten egg. Bake for 40 to 45 minutes, until golden brown.