In a food processor (or blender), add garlic, anchovy paste, parsley, chives, tarragon, and dill. Pulse until finely chopped.
Add mayonnaise, sour cream, lemon juice, and lemon zest. Blend until creamy, smooth, and green, with pretty tiny flecks of herbs.
Season with salt, pepper, and cayenne. Taste and adjust, if desired.
Use as a dip with fresh vegetables or drizzle over a simple leafy-green salad.
