Wash and chop the romaine lettuce, cucumber, tomatoes, red onion, and bell pepper under cold water, then chop into uniform bite-sized pieces.

Finely chop the parsley until you have a generous amount and set aside.

In a medium bowl, mix olive oil, red wine vinegar, Dijon mustard, and minced garlic, whisking until emulsified.

Combine the chopped vegetables, parsley, and grated Parmesan cheese in a large bowl and toss together.

Dress the salad with the vinaigrette and toss gently until evenly coated.

Serve immediately for best texture and flavor.