In a small mixing bowl, whisk together the olive oil, lemon juice, lemon zest, honey, and a pinch of salt and pepper for the dressing.

In a large salad bowl, combine the chopped romaine lettuce, grated parmesan cheese, and sliced red onion.

Sprinkle the crushed red pepper flakes over the salad ingredients.

Drizzle the prepared dressing over the salad and toss gently until evenly coated.

Serve immediately on chilled plates.