Brush four ramekin dishes with a little melted butter. Add a small amount of sugar to each, then turn them to coat the sides and bottom, shaking out any excess.
Bring a little water to a simmer in a pan. Suspend a heatproof bowl over the pan (do not allow the base of the bowl to touch the water). Add the chocolate to the bowl and stir until smooth and completely melted, then set aside to cool slightly. Add the pistachios and stir until well combined.
Pour the cream into a bowl and whip until soft peaks form when the whisk is removed.
In a separate bowl, whisk the egg whites until soft peaks form when the whisk is removed. Add the caster sugar, whisking continuously, until stiff peaks form when the whisk is removed and the mixture is glossy.
Carefully fold the whipped cream into the chocolate and pistachio mixture with a metal spoon. Then carefully fold the whisked egg whites into the chocolate and cream mixture using a metal spoon, until well combined.
Pour the chocolate mousse mixture into the prepared ramekins and chill in the fridge overnight.
For the tuile baskets, preheat the oven to 200C/400F/Gas 6.
In a bowl, beat together the butter, icing sugar and honey until smooth and well combined.
Gradually beat in the egg whites, one at a time, until well combined.
Carefully fold in the flour using a metal spoon. Chill the mixture in the fridge for 2 hours.
Meanwhile, cut a 12-15cm/5-6in disc from the centre of a sheet of plastic or the disused lid of an ice cream carton. (You will need this as a template for the tuile basket.)
Line a baking tray with baking parchment. Place the template onto the lined baking tray. Using a palette knife, spread a thin layer of the chilled tuile mixture over the cut-out part of the template to 'fill' the circular hole, then level off. Carefully remove the template so you are left with a thin, flat disc of tuile paste.
Transfer the tuile disc to the oven and bake for 3-4 minutes, or until pale golden-brown.
Remove the baked tuile disc from the oven. Quickly place a tumbler into the centre of the tuile disc, then turn the glass, tuile biscuit and baking parchment upside-down and shape the tuile mixture around the sides of the glass. Set aside to cool and harden.
Repeat the process with the remaining tuile mixture until you have four tuile baskets.
For the tropical fruit salad, mix together all of the tropical fruit salad ingredients until well combined.
To serve, place one of the cooled tuile baskets into the centre of each of four serving plates. Place a scoop of the chilled chocolate and pistachio mousse inside each basket. Spoon the tropical fruit salad alongside.