- 3 tablespoons unsalted butter
- 1 large fennel bulb, coarsely chopped, plus fennel fronds for serving
- 2 shallots, chopped
- kosher salt and black pepper
- 2 pounds mussels, scrubbed
- 1/2 cup dry white wine
- 3 tablespoons olive oil
- 2 tablespoons white wine vinegar
- 5 ounces mixed greens (about 6 cups)
- country bread, for serving
- Melt the butter in a large pot over medium heat. Add the fennel, shallots, ½ teaspoon salt, and ¼ teaspoon pepper and cook, stirring occasionally, until the vegetables are tender, 4 to 6 minutes.
- Add the mussels and wine and simmer, covered, until the mussels open, 4 to 6 minutes. (Discard any mussels that remain closed.)
- Meanwhile, combine the oil, vinegar, and ¼ teaspoon each salt and pepper in a large bowl. Add the greens and toss to combine.
- Serve the mussels with the cooking liquid. Sprinkle with the fennel fronds and serve with the salad and bread.