Set the slow cooker to high. Heat the oil in a frying pan over a medium heat and fry the chicken and chorizo for 7-10 mins until golden. Transfer to the slow cooker using tongs. Add the onion to the pan and fry for 5-7 mins, or until just softened. Stir in the garlic, paprika and saffron, if using, and cook for 2 mins. Add your rice. Pour in the wine and simmer until reduced by half. Tip into the slow cooker with the tomatoes and stock. Season. Cover and cook for 1 1/2 hrs.

Add the peas and prawns and cook for 30 mins more. Check the rice is tender; if not, cook for another 15-30 mins.

Scatter over the parsley and serve with lemon wedges and crusty bread, if you like.