Mix the salad. In a large bowl, combine the romaine lettuce, radicchio, red onion (or shallots), cherry tomatoes, olives, and pepperoncini. Toss gently to mix.
Make the Italian dressing. In a mason jar or sealable container, add the Italian seasoning, salt, red wine vinegar, and olive oil. Close the lid and shake very well. (Or, add the Italian seasoning, salt, and vinegar to a small bowl. Whisk as you slowly drizzle in the olive oil, whisking until emulsified.)
Dress and serve. Pour the dressing over the salad and toss. Add the shaved parmesan and a dash of black pepper. Taste and adjust seasoning. Mix in the croutons, if using, and serve.
