Soak the bread roll in water.
In the meantime, peel and chop the onions. Sauté briefly in a pan in hot oil.
Squeeze out the breadcrumbs and knead well with the onions, minced meat, egg, salt and spices. If the mixture is too firm, add a little milk. Season to taste.
Shape the mixture into a flat loaf with wet hands and place in an oven-proof dish or baking tray.
Season well with paprika powder and brush with egg white. Bake in the oven at 180 °C for 16 to 17 minutes.
Remove the finished roast from the oven, cut into slices and serve with salted potatoes.