Place all the paste ingredients in a food processor or mini chopper and blend until it forms a paste. Set aside.

Heat the oil in a large pan. Toss the chopped beef in the cornflour, salt, and pepper.

Fry the meat in the oil for about 5 minutes on medium to high heat. You can do this in batches, but I find that if you put the meat in, and leave it alone for a few minutes before you stir it, you'll get a nice dark colour on the beef. The beef will probably stick a bit to the pan, so you might need to give it a little scrape with a spatula.

Once the beef has cooked for 5 minutes, turn down the heat a little and add in the spice paste you made earlier. Give it a stir to coat the beef and let it cook for a couple of minutes.

Add in the beef stock and coconut milk. Give everything a stir (make sure you give any bits stuck at the bottom of the pan a scrape), place the lid on and gently simmer on a low heat for 1 hour 45 mins (alternatively you can place it in the oven at about 160C/320F (fan)). Give it a stir every so often. If it's starting to look dry you can add in some more beef stock or water.

After the 1 hour 45 mins, add in the potatoes, give it a stir and cook for a further 25 - 30 mins until the potatoes are tender (this is a good time to start cooking your rice too).

Take out of the oven and mix in the lime juice. Serve the curry on a bed of rice with a sprinkling of coriander/cilantro, fresh chillies, and a wedge of lime.