Coat the chopped chicken thighs in cornflour (with the pepper already mixed in). I suggest rolling the chicken in the cornflour for an even coating but for speed you could also put them in a plastic food bag and shake until coated.
Fry the coated chicken in oil until the sides are golden and crispy. I find it is best to split the chicken into two batches in order to fry as it won’t crisp up properly if the pan is over crowded.
Mix the sesame oil, rice vinegar, passata, soy sauce, sweet chilli sauce, chilli flakes and sugar and water. If you want your cashews soft add them at this point as well, if you would rather them crunchier add them at a later point.
Let the fried chicken cool slightly to let the coating dry out a little so it doesn’t wash off in the sauce. (I just leave it out whilst I mix up the sauce so it only needs a couple of minutes.
Put the chicken in the slow cooker and pour the sauce over.
Set your slow cooker for low heat and 2 hours. If you skip browning the cornflour coated chicken and want to through the chicken in raw you will need to put it in for 4 hours.
Keep an eye on your sauce, it may dry out and if you want it a bit more ‘saucy’ add a little more water. I tend to add another 100ml of water after about 1 hours.
Serve with rice. If you are feeling fancy or after a more authentic takeaway feel egg fried rice but I like this with just plain white rice.