Why It Works
- Cooking the leeks in the rendered fat from the kielbasa adds a porky, smoky flavor to the base of the soup.
- A combination of fresh cabbage and sauerkraut gives the soup good kraut flavor without making it overly sour.
This recipe takes ideas from traditional Polish kapusniak (sauerkraut soup) and combines them with the creamy texture of potato-leek soup for a bowl that's satisfyingly rich and filling, but with a tangy, bright flavor.
- 2 teaspoons (10ml) vegetable oil
- 1 (12- to 18-ounce) link smoked kielbasa sausage, split in half lengthwise and cut into 1/2-inch slices (350 to 500g)
- 4 tablespoons (60g) unsalted butter
- 2 medium leeks, white and pale green parts only, split in half lengthwise and cut into 1/2-inch pieces (about 8 ounces; 225g)
- Kosher salt and freshly ground black pepper
- 1 pound (450g) Yukon Gold potatoes, peeled and cut into 1-inch cubes
- 5 cups (1.2L) homemade or store-bought low-sodium chicken stock
- 8 ounces white or green cabbage, shredded (225g; about 1/2 medium head)
- 2 bay leaves
- 1 pound sauerkraut with its liquid (450g; about 2 cups)
- Chopped fresh dill and extra-virgin olive oil, for serving
- Fresh crusty bread, for serving
Heat oil in a large saucepan or Dutch oven over medium heat until shimmering. Add sausage and cook, stirring occasionally, until well browned, about 5 minutes. Remove sausage from pan using a slotted spoon, leaving any rendered fat behind. Set sausage aside.
Add butter and leeks to sausage fat in the saucepan. Season with salt and pepper and cook, stirring, until leeks have softened but not browned, about 3 minutes, reducing heat if necessary. Add potatoes and chicken stock, scraping up any browned bits from the sides and bottom of the pot. Add cabbage and bay leaves. Increase heat to high and bring to a boil. Reduce heat to maintain a bare simmer and cook until potatoes are completely tender, about 10 minutes.
Add sauerkraut and its liquid to the pot and bring to a simmer. Discard bay leaves. Working in batches, transfer the soup to a blender and blend, starting at lowest speed and slowly increasing to maximum speed, until soup is completely smooth, about 2 minutes per batch. Transfer the soup to a fine-mesh strainer set over a clean pot, using the back of a ladle to push it through. Season to taste with salt and pepper.
Garnish soup with browned sausage pieces, chopped dill, and olive oil. Serve immediately with crusty bread.
If you'd like more pork flavor, add 8 ounces of well-rinsed salt pork or slab bacon, cut into 1/2- by 1/4-inch lardons, to the kielbasa.