Step 1

Toss the strips of steak, the lemongrass, soy sauce, half the fish sauce, half the sugar and half the chilli flakes together in a bowl. Set aside in the fridge to marinate for at least 20 mins or up to 6 hrs.

Step 2

Mix the remaining fish sauce with the lime juice, remaining chilli flakes, the rest of the sugar and 3 tbsp water, then set aside.

Step 3

Heat 1 tbsp vegetable oil in a large non-stick or cast iron wok or frying pan over a high heat. Once hot, tip in half the marinated steak strips and stir-fry for 2 mins until just cooked through, then remove to a large plate using tongs or a slotted spoon and repeat using another 1 tbsp of oil and the remaining beef. Remove to the plate, then wipe the wok or pan clean using kitchen paper.

Step 4

Add the remaining oil to the pan and fry the green pepper and the white parts of the spring onion. Stir-fry over a high heat for 2-3 mins, then add the garlic and ginger and stir-fry for another 45 seconds-1 min. Return the steak to the pan, stir well, then add the lime dressing and most of the basil leaves, mixing well to coat.

Step 5

Divide the stir-fry between bowls alongside rice or noodles, then scatter with the chopped peanuts, the remaining basil leaves and the green parts of the spring onions.