Polish Christmas Soup: Clear Beet Barszcz with Mushroom Uszka

Polish Christmas soup often means barszcz wigilijny, a clear, tangy beet soup served on Christmas Eve, or Wigilia, commonly with small mushroom-filled dumplings called uszka. This version builds a savory broth with beets, dried porcini, vegetables, and beet kvass; Polish households have regional and family variations, so the balance of sourness and the choice of dumplings can differ.

Ingredients

1 cup (240 ml) hot water, for soaking the mushrooms
¾ oz (20 g) dried porcini mushrooms
2 lb (900 g) raw beets, peeled and cut into roughly ½-inch (1.25 cm) pieces
8 cups (1.9 L) vegetable broth, preferably low-sodium
1 medium yellow onion (about 5 oz/150 g), peeled and quartered
1 medium carrot (about 3½ oz/100 g), peeled and cut into large chunks
1 celery stalk (about 2 oz/60 g), cut into large pieces
½ medium leek (about 3½ oz/100 g), washed well and sliced
1 small tart apple (about 5 oz/150 g), cored and quartered
2 bay leaves
5 whole allspice berries
8 whole black peppercorns
3 garlic cloves (about ½ oz/15 g), lightly crushed
1 teaspoon (1 g) dried marjoram
1½ cups (360 ml) beet kvass, also called beet zakwas, plus more to taste
1 teaspoon (4 g) granulated sugar, optional
1 teaspoon fine salt (about 6 g), then more to taste
1 tablespoon (15 ml) lemon juice, optional, for adjusting the acidity
12 oz (340 g) frozen mushroom uszka, optional, for serving; cook according to the package directions

Instructions

Put the dried porcini in a heatproof bowl and pour over the hot water. Leave them to soak for 20 minutes. Lift the mushrooms out, keeping the soaking liquid, and rinse away any grit. Pour the liquid through a fine sieve lined with a coffee filter or a clean paper towel; porcini can leave sand at the bottom of the bowl. Chop the mushrooms if the pieces are large. This soaking time is separate from the listed 25 minutes of active preparation.
While the mushrooms drain, peel and cut the beets, onion, carrot, celery, leek, and apple as listed. The pieces do not need to be perfectly even because the solids will be strained out, but keep the beet pieces close in size so they soften at a similar rate. Wash the leek between its layers, where soil can collect. Lightly crush the garlic rather than mincing it; that makes it easier to remove when you strain the soup.
In a large, nonreactive pot, combine the beets, onion, carrot, celery, leek, apple, chopped porcini, strained mushroom liquid, vegetable broth, bay leaves, allspice, peppercorns, garlic, and marjoram. Bring just to a boil over medium-high heat, then reduce the heat to maintain a gentle simmer. Partly cover the pot and simmer for 55 minutes, or until a piece of beet is tender when pierced with a knife. Avoid a hard boil, which can make the broth cloudy and can break the vegetables apart.
Set a fine-mesh strainer over a clean pot or heatproof bowl and carefully pour in the soup. Let it drain for about 5 minutes; do not press the vegetables through the mesh if you want a clear broth. Discard the vegetables and spices, or save a few of the porcini pieces to use as a garnish. The broth should be a deep red. If it looks pale, its flavor may still be good; the final acidity and beet kvass will help brighten it.
Return the strained broth to the pot. Stir in the beet kvass and salt, then add the sugar if the soup tastes sharply sour. Warm gently for about 5 minutes, tasting as it heats. Do not boil after adding the kvass: a gentle heat preserves its fresh fermented tang and helps keep the color vivid. Add lemon juice a little at a time if you want a brighter finish, or add more kvass for a deeper fermented flavor. Adjust salt only after these additions.
If serving with frozen uszka, cook them separately according to their package directions while the soup warms; a common cooking time is about 5 minutes, but brands and sizes vary. Drain carefully. Divide the dumplings among warm bowls and ladle the hot barszcz over them, or serve the dumplings on the side so they remain distinct. Serve promptly while the broth is hot.

Tips

Choose the right beet kvass. Beet kvass is a naturally fermented, pleasantly sour beet drink, and the ingredient that gives this soup its characteristic depth. Look for it in Polish or Eastern European grocery shops, or make the soup with ready-made beet zakwas. If it is unavailable, use 2 tablespoons (30 ml) apple cider vinegar or lemon juice in place of the kvass to start, then add more gradually. The substitute supplies acidity but not the same fermented flavor, so the soup will taste simpler and less rounded.
Keep the broth clear. Cut vegetables into large pieces, simmer gently, and strain without pushing down on the solids. A hard boil or squeezing the vegetables can release pulp and make the soup cloudy. Cloudiness does not make it a failure; it will still taste good, especially with dumplings.
Season in stages. Beet kvass varies in saltiness and acidity, and vegetable broths vary too. Add only part of the salt at first, then taste after the kvass goes in. Sugar is a balancing option, not a requirement: use a small amount only if the finished broth tastes harsh rather than pleasantly sour.
Check dumpling ingredients. Uszka can be difficult to find outside Polish or Eastern European shops. Frozen mushroom uszka are convenient, but their fillings and wrappers vary; check the label if you need a vegetarian or dairy-free option. Small mushroom ravioli can stand in, though they are larger, less delicate, and not quite the same traditional accompaniment.

Serving Suggestions

Serve barszcz in small bowls or cups as a first course, with several uszka in each serving. The clear broth is traditionally the focus, so keep garnishes restrained: a few reserved porcini pieces, a little chopped fresh dill, or a small spoonful of finely chopped parsley is enough. If you want to keep the soup especially clear, pass the dumplings separately and let each person add them at the table.

On a Christmas Eve menu, this soup pairs naturally with other meatless dishes, such as pierogi, baked fish, or cabbage and mushroom dishes. For a simple supper outside the holiday season, offer rye bread or boiled potatoes alongside it. The soup is flavorful but light in texture, so a bread or dumpling accompaniment makes the meal more substantial without covering up the beet and mushroom notes.

Variations

Many Polish families serve a different Christmas Eve soup, including mushroom soup, and barszcz itself varies from one household to another. Some versions rely on homemade fermented beet starter, some include dried mushrooms, and some are more sour or more gently sweet. This recipe uses porcini and beet kvass for a balance of earthy and tart flavors, but neither the seasoning nor the choice of accompaniment is universal.

For a stronger mushroom character, soak an extra ¼ oz (7 g) dried porcini and use the strained soaking liquid, keeping the added liquid within the recipe’s overall amount. For a simpler pantry version, omit the apple; the broth will be a little less rounded, so taste and adjust the acidity carefully. If you cannot get uszka, serve the soup plain or with another small mushroom dumpling. A beet soup made with roasted beets can also be delicious, but roasting gives the beets a sweeter, deeper flavor and usually makes the result less like this clear, gently simmered barszcz.

Storage and Reheating

Cool the soup promptly and refrigerate it within 2 hours of cooking. Store the broth in a covered container for 3–4 days; keep cooked uszka in a separate container so they do not absorb the soup and turn soft. Reheat only the amount you plan to serve, in a saucepan over medium heat, stirring occasionally until it reaches 165°F (74°C); check with a food thermometer. Avoid repeatedly bringing the whole pot to a boil, which can dull the flavor and color.

For longer storage, freeze the strained broth in a freezer-safe container for up to 2–3 months for best quality, leaving room for expansion. Thaw it in the refrigerator, then reheat to 165°F (74°C). The color may be slightly less vivid after freezing, but the soup should still be enjoyable. Cook fresh uszka for serving rather than freezing them in the broth.

Frequently Asked Questions

What is Polish Christmas soup called? One well-known Polish Christmas Eve soup is barszcz wigilijny, or Christmas Eve beet barszcz. It is often served clear, with uszka—small dumplings commonly filled with mushrooms. Not every Polish family serves barszcz; mushroom soup and other regional or family traditions are also common.

What is beet kvass, and can I leave it out? Beet kvass, also called beet zakwas, is a fermented beet liquid that adds tartness and a characteristic savory depth. You can leave it out, but the soup will taste less complex. Start with vinegar or lemon juice as a substitute, then taste and adjust rather than replacing the full amount with an equal volume of sharp acid.

Can I make the soup a day ahead? Yes. Make and strain the broth, cool it, and refrigerate it promptly. For the best flavor and color, stir in the beet kvass and make the final seasoning adjustments as you reheat the soup. Cook the uszka separately just before serving so they keep their shape.

Why did my barszcz turn cloudy? The most common reasons are a vigorous boil, finely chopped vegetables, or pressing the cooked solids through the strainer. The soup is still usable if cloudy. Next time, keep the simmer gentle, cut larger pieces, and allow the liquid to drain without squeezing the vegetables.

Can I use fresh mushrooms instead of dried porcini? You can, but fresh mushrooms do not provide the same concentrated, earthy flavor or the useful soaking liquid. Use about 4 oz (115 g) chopped fresh mushrooms, sauté them separately until their moisture cooks off, and add them to the soup before simmering. The broth will be milder and may be less clear.

Is this recipe vegetarian? The soup as written is vegetarian if you use vegetable broth, and it is made without meat. Uszka vary by brand and recipe, so check the filling and wrapper if you need the whole meal to be vegetarian or vegan. Mushroom-filled dumplings are a traditional pairing, but the soup can be served without them.

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