Step 1

Melt the butter in a Dutch oven or other heavy pot over medium heat. When it stops frothing, add the chopped onion and cook gently until its soft and translucent. Do not let it brown.

Step 2

Add the potatoes and coat with the butter. Cook for 1 to 2 minutes to let the butter absorb a bit. Sprinkle everything with salt. Pour in the fish stock, water and marjoram and add salt and pepper to taste. Simmer gently for about 20 minutes, or until the potatoes are tender.

Step 3

Once the potatoes are tender, add the perch and the kielbasa and simmer another 10 minutes. Turn off the heat and add the dill.

Step 4

Ladle into bowls and let everyone add sour cream to taste at the table. Serve with lots of beer. and some crusty bread.