- For the dressing: Combine the basil, olive oil, vinegar, honey, Dijon mustard, shallots and red pepper flakes, if using, in a blender until the dressing emulsifies and the basil is pureed. Season with salt and pepper.
- For the salad: Combine the tomatoes and peaches in a bowl and toss to coat with the dressing. Top with cheese, onion and toasted pecans. Serve at room temperature.