Inspired by the 50's classic Green Goddess, the dressing is the star of this salad. It's a delicious dipping sauce for shrimp or veggies, too.
If you find yourself with leftover dressing, it will keep in the refrigerator (tightly sealed) for up to 3 days.
Combine the first 10 ingredients (anchovies through avocado) in a food processor and pulse to chop. Add the mayonnaise and sour cream, and purée until smooth. Season to taste with salt and pepper.
Place the greens in a large bowl. Add the tomatoes, radishes, cucumbers and dressing. Toss to coat and serve immediately.