Cabbage, Bacon, Parsnip, Sweet Potato, and Chickpea Stew

2 medium leeks, washed and finely sliced
2 parsnips, peeled and cut into ¾" cubes
6 thick slices of bacon, rind trimmed off and cut into ¼"–½" pieces
2 tablespoons butter
2 tablespoons olive oil
¨ö small cabbage (Savoy is good too) cored and finely shredded
10 fresh sage leaves
1 teaspoon fresh thyme
1 small dark-fleshed sweet potato (Garnet or Jewel), cleaned, left unpeeled, but cut into ½" cubes
1 15-oz. can chickpeas (garbanzos) drained and rinsed
4 cups vegetable or chicken stock
Salt and freshly ground black pepper to taste

Heat butter and oil together in a soup pot over medium heat. Add leeks, parsnips, and bacon and cook until the leeks have wilted and browned a bit. Add cabbage, sage, thyme, sweet potato, and chickpeas and stir together. Add stock, raise heat, and bring to a boil. Reduce heat to simmer, and continue cooking till vegetables are tender. Add salt and pepper as needed.