In a blender, combine the olive oil, white wine vinegar, grated Parmesan cheese, mayonnaise, lemon juice, garlic salt, and Italian seasoning. Blend until smooth and creamy.

In a large mixing bowl, combine the American salad blend, sliced pepperoncini peppers, chopped tomatoes, thinly sliced red onion, sliced black olives, croutons, and grated Parmesan cheese. Toss gently to mix.

Toss the salad mixture again and drizzle the homemade dressing over the salad. Toss lightly to coat everything evenly.

Transfer the salad to serving plates and serve immediately, with extra dressing on the side if desired.