Salad of Mixed Greens, Roasted Portobello Mushrooms and Red Onions with Sherry Vinaigrette

VINAIGRETTE :

1 tablespoon Dijon mustard
1/4 cup sherry wine vinegar
Salt and freshly ground black pepper, to taste
Pinch of dried tarragon
3/4 cup extra-virgin olive oil

SALAD :
8 large portobello mushrooms, cut into 1/4-inch-wide slices
4 tablespoons olive oil
4 red onions, peeled, halved and cut into 1/4-inch-wide slices
Salt and freshly ground black pepper
6 cups torn salad greens, such as mesclun mix, red leaf lettuce, Boston lettuce,
Bibb lettuce or green leaf lettuce (see Note)
Shaved Parmesan or pecorino cheese, for garnish

1. To prepare the vinaigrette, combine the mustard and vinegar in a small bowl and whisk well. Season to taste with salt, pepper and tarragon and whisk again. Slowly add the olive oil, pouring it in a steady stream while whisking constantly to emulsify the vinaigrette. Taste and correct the seasoning, if necessary. Set aside until ready to use.
2. Preheat the oven to 350F.
3. To prepare the salad, place the mushrooms in a shallow baking dish lined with aluminum foil, sprinkle with 2 tablespoons of the oil and season to taste with salt and pepper. Toss gently.
4. Spread the onions in another foil-lined baking dish, sprinkle with the remaining 2 tablespoons of oil and season to taste with salt and pepper. Toss gently.
5. Roast the mushrooms and onions for about 1 hour, until very tender. Stir them a few times during roasting. Set aside to cool.
6. To serve, put the greens in a large bowl and toss with about 2 tablespoons of the vinaigrette and then arrange on 6 salad plates.
7. Put the mushrooms in the bowl and toss with about 2 more tablespoons of the vinaigrette. Spoon these over the greens. Put the onions in the bowl and toss with about 1 tablespoon of the vinaigrette. Spoon these over the mushrooms. Top each salad with the shaved cheese and season with freshly ground pepper. Serve immediately.

Note : Use the freshest salad greens available. Many supermarkets and green grocers sell mesclun mix, a mixture of specialty lettuces, which adds lovely flavor, texture and color to any salad. Mix it with other soft, buttery greens.

Serves 6