Tip the onions and leeks into a slow cooker pot and add the potatoes, mixed herbs and stock ... that holds around 4 litres/7 pints for this recipe. To freeze the soup, leave to cool completely ...
Lift into the slow cooker. Push the onion halves into the gaps around the beef, then the potatoes, and finally fit the carrots over and around the top. Put the kettle on. Put half of the cornflour ...