Begin by heating a wok or a large frying pan over high heat until it is smoking hot—this intense heat is key to achieving that signature sear and flavor. Pour in the vegetable oil, swirling it around the pan to ensure an even coating. Immediately add the sliced beef strips along with the sliced red chilli. Continuously stir the meat with a wooden spatula or tongs to promote even browning and to prevent sticking. Cook for about 3 minutes until the beef is lightly browned but still tender. Next, pour over the oyster sauce, allowing it to simmer briefly so it warms through and clings deliciously to each beef strip. Stir in the handful of fresh basil leaves just before removing the pan from heat; the residual warmth will wilt them perfectly, releasing their fragrant essence. For best results, serve this vibrant stir-fry immediately alongside plain steamed rice which balances the bold flavors. As a helpful tip, ensure your all ingredients are prepped and ready before you begin cooking, as the stir-frying process moves quickly and requires your full attention.