- 6 tablespoons black walnut pieces
- 4 teaspoons apple cider
- Salt
- 1 small (1 pound) head green cabbage
- 2 tablespoons butter
- 1 medium white onion, diced
- Salt and freshly ground black pepper
- 3 cups chicken broth
- 3 cups whole fat buttermilk at room temperature
- In a small heavy skillet over medium heat, toast the black walnut pieces, shaking the pan, until they just begin to turn golden, about 3 minutes. Be careful not to burn them.
- Put the toasted walnuts in a blender, add the cider and a large pinch of salt, and pulse until a loose, grainy paste is formed. Remove the pesto from the blender and set it aside.
- Split the cabbage in half, remove the core, and cut each half into 4 wedges. Slice the wedges into thin strips.
- Melt the butter in a Dutch oven over medium heat, and sauté the onion until it just begins to soften, about 4 minutes. Add the cabbage and a few pinches of salt, and stir well to coat with the butter.
- Add the broth and bring to a lively simmer. Cover and simmer for 10 minutes or until the cabbage is tender.
- Remove the pot from the heat and stir in the buttermilk. Return it to very low heat and warm it slowly, stirring as you do, so the buttermilk doesn’t curdle.
- Serve the soup in individual bowls with a tablespoon of the black walnut pesto in the center of each serving. Pass the salt and pepper for additional seasoning.