Start by bringing a large pot of salted water to a rolling boil over high heat. Once boiling, add the rotini pasta and cook according to package instructions until al dente, usually 8-10 minutes. When done, drain the pasta in a colander and rinse it under cold water to halt the cooking process.

In a large mixing bowl, add the cooled rotini pasta along with sliced pepperoni, diced mozzarella, and halved cherry tomatoes. Next, toss in the sliced black olives, diced green bell pepper, and finely chopped red onion. Stir gently to combine all the ingredients.

Pour your Italian dressing over the pasta mixture, ensuring everything gets a nice coating. Toss the salad gently to distribute the dressing evenly across all the ingredients.

Sprinkle dried oregano over the mixture, and add salt and freshly ground black pepper to taste. Mix thoroughly again to ensure the seasoning is well incorporated.

Cover the mixing bowl tightly with plastic wrap or transfer the salad into an airtight container. Place it in the refrigerator for at least 1 hour to let the flavors meld together.

Just before serving, give the salad a good toss to mix everything back together. Taste again to adjust the seasoning if needed.

Finally, transfer the chilled Pizza Pasta Salad to a serving platter or individual bowls and enjoy it cold.