For the filling, fill a large saucepan half-full with water and set over a high heat. Add 1 tbsp salt and bring to the boil. Add the onion, carrot, celery, pepper, garlic and spring onions. Boil for 40 mins to make a stock. Add the chicken breasts and simmer for a further 30 mins.

Meanwhile, for the arepas, mix 900ml water with a generous pinch of salt in a large bowl. Gradually add the harina, gently mixing with your hands until a smooth dough is formed – it should be soft but not sticky. Leave to rest for 3 mins. Separate into 10 pieces and shape into balls. Cover and set aside.

Remove the chicken from the stock using a slotted spoon and leave to cool. Strain the stock, discarding the solids, then measure 100ml into a jug (chill or freeze the rest of the stock to use in another recipe). Shred the poached chicken using two forks, then tip into a bowl with the 100ml stock, the mayonnaise and lemon juice. Mix together well, breaking up the chicken a bit more as you do.

Press the arepa dough balls between your palms into large patties, about 1.5cm thick. Arrange as many as you can comfortably fit into a hot griddle or large frying pan over a medium heat (you'll need to do this in batches). Cook for 5 mins each side until starting to puff up and turn brown. When ready, they should sound hollow when tapped. Wrap to keep warm while you cook the rest.

Meanwhile, for the avocado topping, roughly chop the avocado flesh, then mix with the lime juice, olive oil, mustard and seasoning to taste.

Split the warm arepas at one end, then fill with the avocado topping, chicken mayonnaise and some coriander leaves to serve.