Prep. time: 20 minutes
Cooking time: 5 minutes

1. Clean, wash and drain the salad greens. Divide them among serving plates. Sauté the minced shallot in a little butter; set aside.
2. Slice the kidneys thinly; sauté them for 5 minutes in a skillet over high heat in a mixture of butter and oil, turning to brown on all sides. Season with salt and pepper.
3. Place the kidneys on the salad.
4. Discard the fat from the skillet; deglaze the pan with sherry vinegar; place over high heat; add the shallot. When it begins to bubble, pour the dressing over the salads; sprinkle with hazelnuts and serve immediately.