In a large bowl toss cooked macaroni with celery, red pepper, and carrots.
In a small bowl whisk together mayo, sour cream, sugar, vinegar, mustard, green onions and parsley.
Pour over macaroni and toss to coat. Refrigerate until serving.
TIP: If you decide to include bacon, I suggest cutting it into bite-sized pieces before you fry it. That way it’s ready to be tossed into the salad without further messy crumbling.TIP: Avoid using butter in place of the olive oil to toss the pasta because it will clump when it becomes cold and that changes the salad’s taste. TIP: The flavors meld better if the add-ins are in small pieces or chunks. For example, halve cherry tomatoes, dice the celery, and cube the ham.