Dilly Bean Stew

Name: Dilly Bean Stew
Ingredients: 2 tablespoons unsalted butter, plus more (optional); 2 tablespoons olive oil, plus more; 1 large onion, thinly sliced; kosher salt, freshly ground black pepper; 2 15-ounce cans white beans such as navy, butter, cannellini, drained and rinsed; 4 cups vegetable or chicken broth (or my preference, 4 cups water plus 1–2 tablespoons better than bouillon); ¼ of a head of cabbage, core removed, coarsely chopped (roughly 8–10 ounces); 1 tablespoon white distilled vinegar or fresh lemon juice (lemon juice should be last resort– white distilled vinegar really should be the thing you use here); 1 cup dill, coarsely chopped; Sour cream, if you must