First scratch the length of the sausage casing and remove the sausage. Shape each sausage into 7-8 balls and set them aside.
Put a large saucepan on the stove on the highest setting and dissolve the butter in it. When the butter starts to form small bubbles, add the flour and stir quickly with a whisk. Now slowly add the hot water and keep stirring vigorously so that a lump-free, light, creamy base sauce is created (= roux).
Then add the ketchup. The sauce should be light red and creamy. Now season with broth, salt and a little pepper. Then the dumplings are placed in the sauce and cooked for 15 minutes on a low level. Meanwhile cook the noodles al dente.