Turn the jadgwurst slices first in the flour, then in the beaten egg and finally in the breadcrumbs. Fry the breaded slices in a pan with hot oil until golden brown on both sides.
For the sauce, melt the butter in a saucepan, stir in the tomato paste thoroughly and then stir in the flour. While stirring constantly, add the water and then the ketchup. Season with sugar, salt and pepper to taste.
At the same time as the sauce, cook the pasta according to the instructions on the packet.