Heat the oil in a pan. Cook the onion for 5 minutes over a medium heat. Add the garlic and fennel seeds and cook for a further 1 minute.
Make 300ml chicken stock with ½ the chicken stock cube. Stir in the flour, then add the stock a little at a time, mixing well between each addition. Once it’s all been incorporated, pour in the milk and stir in the potato and sweetcorn. Bring to the boil, then reduce to a simmer. Season with black pepper and cook for 15 minutes until the potatoes are tender. Add the chicken and half the parsley, and heat through until the chicken is piping hot.
Divide between bowls and garnish with the remaining parsley. Serve with the pittas.