Cook the rotini pasta according to package directions until al dente. Drain immediately and rinse well under cold water to stop the cooking process and remove excess starch. Set aside to cool completely.

While the pasta cools, prepare the dressing. In a medium bowl, whisk together the mayonnaise, red wine vinegar, Dijon mustard, Italian seasoning, and garlic powder. Season generously with salt and black pepper. Taste and adjust seasonings as needed.

In a large mixing bowl, combine the cooled pasta with the halved cherry tomatoes, diced cucumber, sliced black olives, diced red onion, and diced pimentos/bell pepper.

Pour the prepared dressing over the pasta and vegetable mixture. Fold gently with a spatula until everything is evenly coated. For best flavor, cover and refrigerate for at least 30 minutes before serving.

To serve as cups, divide the chilled pasta salad evenly among 8 individual small containers, ramekins, or clear plastic cups. Garnish each cup with a sprinkle of fresh parsley, if desired.

Keep refrigerated until ready to serve. These salad cups are excellent for grab-and-go lunches.