Prepare the sauce: In a small bowl, whisk together the fish sauce, dark soy sauce, light soy sauce, brown sugar, water, and the cornflour slurry. Set aside. You’ll notice the sauce looks dark and glossy — that’s the promise of a beautiful glaze.

Prepare the beef: Pat the sliced beef dry with kitchen paper. This is crucial for achieving a good sear. Season it lightly with a pinch of white pepper. You should feel the beef is completely dry to the touch, which will help it brown rather than steam.

Get the pan screaming hot: Place your large frying pan or wok over the highest heat for a good two minutes. Add the oil and swirl it around. The oil should shimmer and just begin to smoke — that’s your cue that it’s hot enough. You’ll hear an immediate, sharp sizzle when the beef hits the pan.

Sear the beef in batches: Add half the beef in a single layer. Do not overcrowd the pan. Let it sear undisturbed for 45-60 seconds until the underside is deeply browned and caramelised. The smell will be rich and savoury. Flip and cook for another 30 seconds. Transfer to a plate. Repeat with the remaining beef. The beef should look beautifully browned, not grey or watery.

Cook the aromatics: Reduce the heat to medium-high. Add a tiny splash more oil if needed. Tip in the sliced onion and bell pepper. Stir-fry for 2 minutes until they soften and the onion becomes translucent. The aroma will be sweet and mellow. Add the minced garlic and sliced chillies. Stir-fry for just 30 seconds until fragrant — the garlic will release a wonderful, heady perfume.

Combine and sauce: Return the seared beef and any resting juices to the pan. Give the sauce a quick stir and pour it in. Toss everything together for 1-2 minutes until the sauce thickens and glazes each piece of beef and each vegetable. The sauce will bubble and become sticky, clinging to everything in a rich, dark coating.

Finish with basil: Turn off the heat. Add the fresh basil leaves and toss gently until they wilt from the residual heat. The leaves should turn a vibrant, dark green and release a wonderfully peppery, anise-like fragrance. Serve immediately.