In a medium bowl, whisk together the olive oil, lemon juice and zest, honey, and a pinch of salt and pepper until smooth and creamy.

In a large salad bowl, combine the chopped romaine lettuce, grated parmesan cheese, sliced red onion, and crushed red pepper flakes. Toss lightly.

Drizzle the prepared dressing over the salad and gently toss everything together to coat the greens.

Serve the salad immediately to maintain freshness, transferring it to serving plates.