Minestrone with Sole

Ingredients

1. 1 tablespoon butter
2. 3 tablespoons olive oil
3. 1 onion, chopped
4. 2 cloves garlic, minced
5. 2 carrots, cut into 1/4-inch dice
6. 2 ribs celery, cut into 1/4-inch dice
7. 3/4 pound boiling potatoes (about 2), peeled and cut into 1/4-inch dice
8. 1 zucchini, cut into 1/4-inch dice
9. 1/4 head cabbage (about 3/4 pound), shredded
10. 3 3/4 cups canned low-sodium chicken broth or homemade stock
11. 1 1/2 cups drained and rinsed canned pinto beans (one 15-ounce can)
12. 1 tablespoon tomato paste
13. 1 1/2 teaspoons salt
14. 1 1/2 pounds sole fillets, cut into 1-inch pieces
15. 2 tablespoons pesto, store-bought or homemade
16. 1/4 teaspoon fresh-ground black pepper

1. In a large pot, melt the butter with the oil over moderate heat. Add the onion and cook, stirring occasionally, until golden, about 5 minutes. Add the garlic, carrots, celery, and potatoes and cook, stirring occasionally, for 5 minutes. Add the zucchini and cabbage and cook, stirring occasionally, for 5 minutes longer.
2. Add the broth, beans, tomato paste, and salt and bring to a simmer. Simmer, partially covered, until the vegetables are tender, about 18 minutes. Add the sole, pesto, and pepper and bring back to a simmer. Cook, uncovered, until the fish is just done, about 1 to 2 minutes more. To serve, ladle into bowls and pass more pesto if you like.