Bring 250ml of water to a boil in a pan and melt 100g of butter into it.
Sieve 125g flour, salt, and sugar and add to the boiling mixture.
Beat the mixture with a wooden spoon until it forms a smooth dough that leaves the pan sides.
Cool the dough, then gradually beat in 4 eggs until it reaches a firm dropping consistency.
Preheat the oven to 200°C and lightly sprinkle a baking tray with water.
Pipe 5cm diameter dough buns onto the tray using a plain-nozzle piping bag.
Bake for 20-25 minutes until the buns are puffed, golden, and crisp.
Pierce a hole in the base of each slightly cooled bun and allow them to cool completely.
Melt the chocolate in a bowl over a pan of gently simmering water.
Stir in 3 tbsp of golden syrup and the orange juice to form a smooth sauce.
Whip 300ml of cold double cream until soft peaks form.
Fold in 75g of chopped pistachios and add icing sugar to taste.
Fill a piping bag with the cream and pipe into the cooled profiteroles.
Arrange the profiteroles on a plate and drizzle with the warm chocolate sauce.