This is called Pea Sausage but it does not contain any sausage. It is a powder pressed into discs and packed into aluminum covered paper and rolled into a sausage. That makes it easy to carry and feed people in outdoor situations. It was developed 1867 from a cook and later sold to the Prussian army. They mass produced it and fed their soldiers during the German-French War 1870-1872. Later the Heilbronn based food producer Knorr bought the recipe and since 1889 you can buy it. But the ingredients today are different. MSG and yeast extract and palm oil are in this soup.
But it just tastes good and with a little extras, as sausage and onion it is a real Fast Food.
Just press two pieces in a pot, use a fork to mash them, measure 500 ml water and just add a little big of it to make a paste. Add the rest of the water and bring it to a boil and cook for 3 minutes.
You can now eat the soup as it is. With a chunk of bread you can feel like an old time soldier, he had to eat that during the whole time in the fields.