Rustic, comforting, and so simple to make, this soup is great for a busy weeknight. Don't skip the apple cider vinegar (and add more to taste). The tangy flavor from the vinegar is what brings everything together. Smarts #1: Angel hair coleslaw mix will cook down fairly quickly, but regular coleslaw mix or hand-sliced cabbage will take slightly longer. Be sure the cabbage is very tender and silky before continuing with the rest of the recipe. Smarts #2: This recipe could be made in the Instant Pot. For tips, join the Cook Smarts Instant Pot Facebook Group.
Heat a Dutch oven or stockpot with oil over medium-high heat. Add onions and kielbasa and saute until onions are very tender and kielbasa is starting to brown, 8 to 10 minutes.
Stir in paprika, oregano, red pepper flakes (if using), garlic, and coleslaw mix. Saute until cabbage is very soft and silky, another 6 to 10 minutes.
Add stock and potatoes and cover with a lid. Simmer until potatoes are tender, ~20 minutes. (Be sure to keep the pot covered so the soup doesn't reduce down too much as everything cooks.)
Stir in beans until heated through, 2 to 3 minutes.
Stir in vinegar and season soup with some salt and pepper. Add additional vinegar if you’d like the soup more tangy.