• Prepare the pork shoulder by cutting away the skin and any visible fat, then cutting it into four large pieces. Rub the pork with salt generously, then place it on the bottom of the slow cooker.
• Mix together the crushed tomatoes, beer, cumin, oregano, dried coriander, chilli powder and chipotle paste. Pour over the pork, then add the chopped onions, crushed garlic and 1 bay leaf. Mix, cover with a lid and cook on HIGH for 6 hours or on LOW for 8-10 hours. By the end of the cooking time the pork should be easily pulled away by a fork.
• With a slotted spoon remove the pork to a large bowl and with two forks pull the meat apart, cover and set aside until later. Set the insert of your slow cooker on the stove top (but only if it's made for it!), turn the heat to medium high and reduce the liquid by a third. Alternatively, you can pour the liquid into a saucepan if your slow cooker insert is not metal and not made for the stove top.
• Add the shredded pork to the reduced liquid and mix the meat in with the juices.

For the Cilantro Lime Slaw

• Slice the cabbage thinly. (I like using either a food processor or a mandolin for this task.) In a large bowl combine the sliced cabbage, chopped cilantro, freshly squeezed lime juice and sour cream. Salt to taste.

Assemble the Tacos

• For best results warm up soft tacos before filling them with pulled pork. (I prefer cooking them briefly on a dry frying pan but you can also use a microwave.) Then fill with pulled pork and cilantro lime slaw. Serve immediately.