Butter Lettuce Salad with Zesty Green Goddess Dressing

Name: Butter Lettuce Salad with Zesty Green Goddess Dressing
Ingredients: 1 cup fresh parsley leaves; 3/4 cup fat-free Greek yogurt; 1/4 cup chopped fresh chives; 1/4 cup freshly squeezed lemon juice (from 2 to 3 lemons); 1/4 cup mayonnaise; 3 tablespoons fresh tarragon leaves; 1/2 teaspoon kosher salt; 1/4 teaspoon freshly ground black pepper; 1 clove garlic, smashed and peeled; 1 scallion, root and dark green part removed, roughly chopped; 1 large head butter lettuce, cleaned and torn into bite-size pieces