Bring a large pot of salted water to a rolling boil and add the broken spaghetti pieces. Cook according to package directions until al dente, usually 8 to 10 minutes, stirring occasionally to prevent clumping.

Drain the cooked spaghetti in a colander and rinse thoroughly under cold running water until completely cool to the touch. Shake the colander vigorously to remove excess water, then spread the pasta on a clean kitchen towel for a few minutes.

While the pasta cools, dice the cucumber, bell peppers, and red onion into uniform bite-sized pieces. Halve the cherry tomatoes and slice the black olives if they aren't pre-sliced.

Cut the cheddar cheese into small cubes, roughly half-inch pieces that match your vegetable size. If using pepperoni, quarter each slice into smaller wedges.

Transfer the cooled spaghetti to your largest mixing bowl and add all the prepared vegetables, cheese, olives, and pepperoni if using. Toss gently with your hands or a large spoon to distribute ingredients evenly throughout.

In a separate small bowl, combine the Italian dressing with grated Parmesan cheese, Italian seasoning, garlic powder, and black pepper. Whisk together until the seasonings are fully incorporated and the Parmesan is evenly distributed.

Pour the seasoned dressing over the pasta and vegetable mixture, starting with about three-quarters of the bottle. Toss everything together thoroughly, ensuring every strand of pasta gets coated, then add more dressing if needed.

Cover the bowl tightly with plastic wrap or transfer to an airtight container and refrigerate for at least 2 hours, preferably overnight. Stir the salad once or twice during chilling if you remember.

Remove the salad from the refrigerator about 15 minutes before serving to take the chill off. Taste and adjust seasoning with additional Italian seasoning, salt, or pepper if needed, and toss once more before serving.