1
Blend anchovies, garlic, mayonnaise, sour cream, basil, parsley, tarragon, 1 tablespoon lemon juice, and 4.5 teaspoons oil in a blender until smooth with only a few flecks of green; season dressing with salt.
2
Combine greens, radishes, and remaining 1 tablespoon plus 1 teaspoon lemon juice in a large bowl, drizzle with oil and season with salt. Toss to combine.