Cook the pasta until it reaches an al dente consistency. Once cooked, drain the pasta, rinse it with cold water to cool it down, and drain it again. Set it aside.
Prepare the fresh vegetables and herbs by chopping the celery, dicing the tomatoes (optional: remove the seeds), finely chopping the peppers (choose a variety of colors for added visual appeal), shredding the carrots (remember to remove excess moisture by squeezing them between paper towels), finely chopping the red onion (soak it in cold water for a few minutes and then drain), slicing the scallions into thin rounds, and chopping the fresh parsley. Set these ingredients aside.
In a mixing bowl, combine the mayo, sour cream, cider vinegar, sugar, dry yellow mustard, kosher salt, and freshly cracked black pepper. Whisk the dressing ingredients together until they are nicely incorporated. Set the dressing aside.
Take a large bowl and combine the cooked pasta, fresh vegetables, and herbs. Add half of the prepared dressing to the bowl and mix everything together thoroughly. Make sure all the ingredients are evenly coated with the dressing.
Cover the bowl and chill the macaroni salad in the refrigerator for at least two hours. This allows the flavors to meld together and enhances the taste. For an even creamier consistency, you can add more dressing as needed or desired before serving.