Preheat the oven to 200C/180C Fan/Gas 6. Grease two baking trays and line them with baking paper.
For the choux, put the cold water, sugar, butter and salt into a small saucepan and pop it on to the hob. On a medium heat, heat the mixture, taking it off as soon as it comes to the boil and all the butter has melted.
Add all the flour at once, stirring vigorously to avoid any lumps.
Take off the heat and step away for a few minutes to allow it to cool just slightly. Now add the eggs a little at a time, making sure to stir all the time – it will look bitty and not smooth, but the more you mix, the more the mixture will come together. It should be a smooth paste. When the spoon is lifted the mixture should drop in a ‘V’ shape, and that’s the perfect consistency.
Pop the mixture into a piping bag, or a zip-lock bag, and snip off the end, 2cm/¾in wide. Pipe small mounds on to the prepared baking trays. Or you could just dollop teaspoons of the mixture on to the baking trays.
Wet the tips of your fingers and pat down any peaks – this will prevent the choux from burning in the oven. Bake for 25–30 minutes. Once baked, the choux should be light and crisp. Remove from the oven, cut in half horizontally, then put them back into the oven to dry a little more.
While the choux are crisping up, make the mackerel pâté. Put the mackerel, yoghurt, butter, salt and pepper into a food processor and blend to a smooth paste. If the mixture is too stiff, keep adding a little more yoghurt, a spoonful at a time, until the mixture is smooth and glides effortlessly in the processor. Transfer to a serving bowl, cover and place in the fridge.
For the chutney, drain the pineapple chunks in a sieve and use the back of a spoon to squeeze out any extra moisture. Pop the chunks into a blender, along with the coriander, chillies, lime juice and zest. Blend to a smooth green paste. Have a taste – there should be a good balance of sweet and salty. Adjust by adding sugar or salt, if needed.
I like to put the crisp choux in the centre of the table, with the pâté and chutney, and let everyone make their own by sandwiching the choux halves with the pâté and adding a generous helping of chutney. But if I’m having people round, I will assemble it in advance.