Ingredients:
1 poundsmoked kielbasa, aka Wedding Sausage, cut into 3 or 4 pieces
3 medium Yukon gold potatoes (about 2 pounds), peeled and quartered
4 cupschicken stock or broth
1/2 teaspoonwhole black peppercorns
2 to 3 dried bay leaves
3 teaspoons(or more) kosher salt
3 tablespoonsunsalted butter
2 medium yellow onions (about 8 ounces), peeled and cut into ½-inch pieces (about 2 cups)
2 celery stalks, cut into ½-inch pieces (about 1 cup)
1 parsnip (about 6 ounces), peeled, and cut into ½-inch pieces (about 1 cup)
2 small carrots (about 6 ounces), peeled and cut into ½-inch pieces (about 1 cup)
6 garlic cloves, peeled, smashed, and coarsely chopped
5 slices seedless light rye bread or rye sourdough bread
2 tablespoonswhite wine vinegar or distilled white vinegar
1/2 teaspoonfreshly ground black pepper
3/4 cupsour cream
1/4 cuppacked finely chopped parsley, plus more for serving
6 to 12 hard-boiled eggs
Directions:
In a large saucepan, bring the sausage, potatoes, broth, peppercorns, bay leaves, 1 teaspoon of the salt, and 4 cups of water to a boil. Reduce the heat to medium-low and simmer, uncovered, for 20 minutes. (Now would be a great time to chop/prep the vegetables.)
In a large heavy stockpot over medium heat, melt the butter. Cook the onion, stirring occasionally, for 3 to 5 minutes, until softened and translucent. A little color is okay. Add the celery, parsnip, carrot, and 1 teaspoon of the salt. Stir to combine, then cover and cook for 5 minutes, stirring once or twice more. Add the garlic and cook, stirring constantly, for about 1 minute, until slightly softened and fragrant.
Ladle 1 cup of the simmering broth from the saucepan and pour into the pot of vegetables. Using a wooden spoon, scrape and release any browned bits from the bottom and sides of the pot while the broth bubbles. Reduce the heat to low, cover, and cook, stirring occasionally, for 15 minutes.
Once the sausage has plumped up and is no longer wrinkled, remove the sausage from the broth and transfer to a cutting board. Test the potatoes for doneness with a fork: if a fork easily slides into the potato or the potato breaks in half, they are ready. Remove from the heat.
Remove and discard the bay leaves. Carefully transfer the broth and potatoes to the pot with the vegetables, starting with a slotted spoon to transfer the potatoes, then finishing with the broth to prevent hot splatter. Stir to combine.
Add the bread, vinegar, black pepper, and 1 teaspoon of the salt. Cover and simmer over low heat, stirring twice, for about 10 minutes, until the bread is ultra-soggy and easily breaks apart as you stir. While waiting for this last bit of cooking time to pass, slice the sausage into half-moons, slice or quarter the hard-boiled eggs, and divide among bowls.
Remove the pot from the heat. Using an immersion blender (or in batches with a standard blender), very carefully blend the hot soup until smooth. Add the sour cream and parsley, then stir (or blend once more) until fully combined and no streaks of sour cream remain. Taste and season with salt and pepper. Ladle the soup over the eggs and sausage. Garnish with more parsley before serving.
Do Ahead: The soup can be made 4 days ahead. Store the soup separately from the sausage and hard-boiled eggs in the refrigerator. Reheat in a saucepan with a splash of water over medium-low heat, stirring frequently until hot and steaming, but not boiling.