This is delicious atop any type of salad greens, fresh tomatoes, or hard-boiled eggs.
1 cup good mayonnaise (or substitute half with greek style yogurt)
1 cup chopped scallions, white and green parts
1 cup chopped fresh basil leaves
1/4 cup freshly squeezed lemon juice (2 lemons)
2 teaspoons chopped garlic (2 cloves)
2 teaspoons anchovy paste (optional)
2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
1 cup sour cream

Place the mayonnaise, scallions, basil, lemon juice, garlic,anchovy paste, salt and pepper in a blender and blend until smooth. Add the sour cream and process just until blended. (If not using immediately, refrigerate the dressing until ready to serve.)

recipe adapted from Ina Garten's," The Barefoot Contessa at Home"