Chill the lettuce: Pop the head of iceberg in the fridge for at least 30 minutes beforehand. Cold lettuce stays crisper and tastes fresher.
Prep the dressing: In a small bowl, whisk olive oil, vinegar, Dijon, honey, garlic, salt, pepper, and red pepper flakes until emulsified.
Taste and adjust salt or vinegar.
Wash and dry: Remove any wilted outer leaves. Cut the head into quarters, remove the core, then chop into bite-size pieces. Rinse and spin dry thoroughly. Dry lettuce is key to a glossy, clinging dressing.
Slice the veggies: Thinly slice the red onion and cucumber.
Halve the cherry tomatoes. Roughly chop the herbs. Keep everything bite-sized.
Assemble: Add lettuce to a large bowl.
Scatter on onions, tomatoes, cucumber, and herbs. If using, add feta and toasted breadcrumbs or croutons.
Dress lightly: Drizzle about two-thirds of the dressing around the bowl’s sides (not straight on top). Toss gently with clean hands so every leaf gets a thin coat.
Add more dressing if needed.
Finish and serve: Taste for salt and acidity. Add a pinch more salt or a few drops of vinegar if it needs brightness. Serve immediately while crisp.