Roast Beef and Endive Salad

INGREDIENTS

• Kosher salt and freshly ground pepper
• 1/2 cup coarsely chopped walnuts
• 2 shallots, finely chopped
• 1/2 cup extra-virgin olive oil
• 1/4 pound gruyere cheese
• 3 tablespoons chopped fresh tarragon
• 3/4 pound thick-cut deli roast beef, fat trimmed
• 5 heads endive
• 1/3 cup coarsely chopped cornichons or dill pickles
• 2 tablespoons red wine vinegar
• 2 tablespoons dijon mustard
• 1/4 cup chopped fresh parsley