Roughly chop the mushrooms, onions, tomatoes and slice the sweet potatoes into chunky 2cm rings. Put it all into the pot along with the chicken, herbs, passata and stock. Stew in your slow cooker on a medium heat for a minimum of 6 hours, the longer the better.
I usually put mine on in the morning before I leave at 8.30 and then eat it 11 hours later.
About 20 minutes before you're ready to eat, place your curly kale on a baking tray with a dash of oil and pinch of salt. Bake for 10-15 minutes on 160 until nice and crispy.
Serve with a dollop of greek yoghurt and lots of black pepper. Delicious!
Note: If you aren't using a slow cooker, you want to cook this in a casserole dish with a lid for a minimum of 3 hours on 160. 30 minutes before its done place the kale on top of the stew then put the lid back on top. Bake in the oven for 30 minutes then its ready to serve :).