Chicken and Romaine Salad with Homemade Ranch Dressing

Dressing

• 1 cup mayonnaise
• ⅔ cup buttermilk
• ¼ cup coarsely grated yellow onion (use the large holes on a box grater)
• 1 tablespoon cider vinegar
• ½ teaspoon celery seed
• ½ teaspoon celery salt
• 1 garlic clove, minced or pushed through a press
• ¼ teaspoon freshly ground black pepper

• 4 boneless, skinless chicken breast halves, each about 6 ounces
• 2 hearts of romaine, each cut lengthwise in half, trimmed
• Extra-virgin olive oil
• 1 pint small cherry or grape tomatoes, each cut in half
• 2 tablespoons finely chopped fresh Italian parsley leaves
• Kosher salt
• Freshly ground black pepper