Blanch the broccoli florets in boiling water for 1–1½ minutes. Remove and place in a bowl of cold water or running water to ensure a crispy texture.
Dry-fry the sesame seeds in a nonstick frying pan over a medium heat. Shake the pan to move the seeds around for 3–4 minutes or until the seeds are lightly browned and popping. Spoon into a small bowl.
Heat the oil in a wok or large frying pan. Stir-fry the garlic, onion and red pepper over a medium heat for 1–2 minutes or until the garlic has lightly browned. Add the broccoli, duck, ginger, stock or water, soy sauce and oyster sauce and stir-fry for 3–4 minutes or until the duck is cooked as you like it. Taste and adjust the seasoning.
Spoon on to a warm serving plate and sprinkle with the sesame seeds. Serve with boiled rice or spoon over cooked noodles.