Heat the oil in a frying pan over a medium heat. Add the onion and chilli and fry until the onion is soft and translucent. Remove from the heat, add the butter and let it melt. Finally, add the shrimps and lime rind. Season the shrimps with a squeeze of lime juice to taste and some salt and pepper.
Spoon the mixture into individual ramekins or a large serving ramekin. Cover and place in the refrigerator for at least 2 hours, or until the butter has set. (This can easily be done the day before.) Remove from the refrigerator 20 minutes before serving.
Place the softened butter in a small bowl. Mix in the garlic, coriander and parsley and season to taste with salt and pepper. Make a cut in each pitta bread to open up the pocket inside and spread with 1 teaspoon of the butter mixture.
Wrap the pitta breads in foil and place in a preheated oven, 180°C (350°F), Gas Mark 4, for 8–10 minutes, or until warmed through and the butter has melted. Serve with the potted shrimps.