Step 1: In a small bowl or a jar with a tight-fitting lid, combine the red wine vinegar, minced garlic, dried oregano, Dijon mustard, red pepper flakes (if using), salt, and black pepper. Whisk vigorously or shake well to combine.
Step 2: Slowly drizzle in the extra virgin olive oil while continuously whisking or shaking until the dressing is emulsified. Taste and adjust seasonings as needed. Set aside.
Step 3: In a large salad bowl, combine the chopped Romaine lettuce, thinly sliced red onion, diced tomatoes, sliced cucumbers, radishes, and black olives. Ensure all vegetables are thoroughly dried.
Step 4: Add the croutons to the bowl.
Step 5: Just before serving, pour about half to two-thirds of the prepared dressing over the salad ingredients.
Step 6: Gently toss the salad to ensure all ingredients are evenly coated with the dressing.
Step 7: Top the salad with freshly shaved or grated Parmesan cheese. Serve immediately and enjoy your classic Italian salad recipe.