Grilled Steak and Peach Salad

Name: Grilled Steak and Peach Salad
Ingredients: For the steak:; 1 1/4 cups extra-virgin olive oil; 3 sprigs rosemary; 1 12-ounce New York strip steak; Kosher salt and freshly ground black pepper; For the dressing:; 1/2 pound blue cheese, crumbled; 1/3 cup sour cream; 1 tablespoon fresh lemon juice; 1 tablespoon red wine vinegar; Pinch of cayenne pepper; 2 teaspoons minced fresh chives; For the salad:; 2 peaches, halved and pitted; 4 cups mesclun greens (about 3 ounces); 2 tablespoons chopped fresh chives; 3 tablespoons thinly sliced fresh basil; 1 tablespoon chopped fresh tarragon; Freshly ground black pepper