This makes enough dressing for us to use on future salads. It is absolutely delicious. I am not a fan of Lima beans but this salad is the exception. You can use frozen sweet corn when fresh is out of season, I just put it in a colander and run warm water over the corn while I am working on other things to thaw but not cook.
Bring approximately 1 cup of lightly salted water to a boil in a small saucepan. Add lima beans. Cook for about 15 minutes. Meanwhile, cut corn kernels from cobs and set aside. Remove lima beans from saucepan with a slotted spoon; set aside. Add corn to hot water in saucepan. Simmer for 3 minutes or until tender; drain and set aside.
For dressing, in a blender combine buttermilk, avocado, parsley, salt, onion powder, dry mustard, pepper and garlic. Cover and blend until smooth. Pour into a serving dish or small pitcher.
Place lettuce on 4 plates. Arrange vegetables and bacon in rows on top of lettuce. Serve with dressing.