Salt and dry the zucchini. Rest 15–20 minutes. Pat completely dry. Brush lightly with olive oil.
Make the sauce. Pulse walnuts until coarse. Add yogurt, garlic, mint, lemon, olive oil, salt and white pepper. Pulse briefly until thick and textured. Refrigerate.
Heat a cast-iron grill pan until smoking.
Grill zucchini in batches. Press firmly for the first 30 seconds.
Cook 3–4 minutes until deeply charred. Turn and cook another 2–3 minutes.
Crisp herbs and garlic in olive oil until golden.
Spread yogurt sauce onto a platter.
Arrange zucchini.
Scatter capers, crispy herbs and garlic.
Finish with Aleppo, flaky salt and olive oil.
Serve immediately.
