Method
1. Get started:
Preheat your oven to 160C / Fan 140C / Gas 3. Unwrap your brisket and pat dry with kitchen paper. Leave it to come to room temperature (about 30 mins).
2. Zest the lime into a jug and crumble in the beef stock cube. Finely slice the chilli and add along with the Thai red curry paste and 400ml boiling water. Stir well to combine.
3. Place a heavy-based casserole or large, ovenproof pan on a medium-high heat for a few mins. When smoking hot, add 1 tbsp oil and the brisket. Sear for 3-4 mins on each side, turning often, till well browned. Take the pan off the heat.
4. Pour over the contents of the jug. Turn the brisket over a couple of times to coat in the sauce, then pop a lid on the pan (or cover with a double layer of foil). From this point, follow either cooking option below.
5. Cooking indoors:
Slide the brisket into the oven. Roast for 3½ hrs, turning a couple of times and basting the brisket. Add a splash more water if it looks like it's getting too dry.
6. Bring a frying pan to a medium-high heat. Tip in the cashew nuts and cook for 3-4 mins, turning frequently, till toasted and brown. Allow to cool slightly, then roughly chop and pour into a bowl.
7. Pick and roughly shred the mint leaves.
8. Remove the brisket from the oven, lift out onto a board, loosely cover with foil and rest for 30 mins.
9. Put the pan of cooking liquid over a high heat and bring to the boil. Reduce till about 150-200ml of the sauce remains. Remove from the heat. Return the brisket to the pan. Spoon the sauce over the meat to glaze it. Slice thinly with a sharp knife or shred with forks and finish with a scattering of toasted cashews, the chopped mint leaves and wedges of lime.
10. Cooking outdoors:
Slide the brisket into the oven. Roast for 3 hrs, turning a couple of times and basting occasionally. Add a splash more water if it looks like it's getting too dry.
11. Bring a frying pan to a medium-high heat. Tip in the cashew nuts and cook for 3-4 mins, turning frequently, till toasted and brown. Allow to cool slightly, then roughly chop and pour into a bowl.
12. Pick and roughly shred the mint leaves.
13. With around 1 hr of cooking time left, light the coals on your barbecue and bring to a medium-low heat. When the brisket has cooked for 3 hrs, remove the lid and place the pan directly onto the coolest part of the grill. Cover the barbecue and gently cook the brisket for 20-30 mins, basting it once or twice with the sauce.
14. Carefully remove the brisket from the barbecue (the pan will be very hot!), lift out onto a board, loosely cover with foil and rest for 30 mins. Put the pan of cooking liquid back on the hottest part of the barbecue. Bring to the boil, and reduce till 150-200ml of the sauce remains. Return the brisket to the pan and glaze. Thinly slice or shred with forks, and finish with a scattering of toasted cashews, the chopped mint leaves and wedges of lime.