Substitute sirloin roast with boneless short ribs or boneless brisket.
Pre-heat the oven to 160°C/320°F.
In a bowl, combine the hoisin sauce, beef stock, rice wine vinegar, ginger and chilli flakes. Set aside.
Pour a splash of olive oil in a hot pan and lightly brown all sides of the sirloin roast, including the ends, to seal the meat and lock in the juices.
Place the beef in an oven-safe dish and pour over the hoisin cook-in sauce.
Cover the roast with tinfoil and cook in the oven for 1 ½ hours turning the beef half way through cooking.
Once the beef is ready, remove from the oven and leave it to cool slightly.
Using two forks or your hands, pull the beef apart to create a shredded texture. Return the pulled beef to the dish and coat in the sauce.
Tear the lettuce leaves off at the base of the head of lettuce. Spoon the shredded beef into the lettuce leaf ‘cups’ and sprinkle over spring onions, sesame seeds and chilli. Squeeze fresh lime juice over the top and serve.