2 tablespoons vegetable oil
1 pound lamb stew meat, cubed
2 cups beef broth
1 cup dry red wine
2 cloves garlic, minced
1 tablespoon chopped fresh thyme
1/4 teaspoon salt
1/4 teaspoon black pepper
1 bay leaf
2 cups peeled, seeded, and sliced butternut squash
1 cup peeled, sliced parsnips
1 cup peeled, chopped sweet potatoes
1 cup sliced celery
1 medium onion, thinly sliced
1/2 cup sour cream
3 tablespoons all-purpose flour