Put the cooking oil in a pan over medium high heat and brown the pork all over.
Scatter the onion, garlic and ginger around the bottom of the slow cooker. Add the gochujang, gochugaru, soy sauce, vinegar and honey and stir to combine. Add the water and stir again.
Place the pork in the slow cooker, fat side up, and season with salt and pepper. Put the slow cooker on low and allow the pork to cook for 3 hours.
After 3 hours, add the potato, carrot and chillies, turn the slow cooker to high and cook for another 3 hours. (While adding the potatoes and carrots, you may find it easier to remove the pork, add the veg, stir, and then add the pork back in afterwards depending on the size of your slow cooker)
Remove the pork from the slow cooker and transfer to a chopping board. When it’s cool enough to handle, cut it into chunks (it should fall apart easily).
Pour the liquid from the slow cooker through a sieve or colander into a large saucepan. Bring the liquid to a boil, then reduce to a simmer. Add the sesame oil, stir and allow the sauce to cook for another 15 minutes to reduce.
Combine the sauce, pork chunks, and vegetables back together. Serve over rice with sesame seeds, fresh coriander and red chilli sprinkled on top.