Peel the pineapple, halve lengthwise, then cut into small slices. Slice off the top and bottom of the clementines, then peel all round the fruit down to the flesh. Cut the clementines into slices. Mix all the fruit together with the honey and vodka. Cover and chill for at least 30 mins.
Boil the sugar and water in a wide stainless steel pan without stirring. Reduce the heat and simmer, swirling the pan occasionally until a light brown caramel has formed. Remove the pan from the heat. Add the pistachios, glaze with the caramel, immediately pour onto a tray lined with baking paper, allow to cool. Roughly chop the caramelized nuts.
Plate up the fruit salad, top with the pistachio brittle.