3 tablespoons (45ml) vegetable oil
1 medium yellow onion, diced (about 1 cup; 200g)
2 medium stalks celery, diced (about 3/4 cup; 100g)
3 medium cloves garlic, crushed
8 ounces (225g) cremini mushrooms, stemmed, caps diced
3/4 pound (340g) smoked pork sausage, such as andouille, sliced into half moons
6 cups (1.5L) homemade chicken stock, store-bought low-sodium broth, or water
1 pound (450g) dry black beans, picked over for shells
3 sprigs fresh thyme
1 bay leaf
Kosher salt
1 cup (240ml) sour cream
1 teaspoon zest from 1 lime
1/8 teaspoon ground cumin
Freshly ground black pepper
Cilantro leaves, for garnish (optional)