Break the chocolate into pieces and place in a saucepan with water, caster sugar, butter and vanilla. Place over a low heat and stirring continuously.
When all has melted together, the sauce is ready. Keep on a very low heat until you’re ready to use, but be careful not to let the sauce start to burn.
Split the profiteroles in half and fill with scoops your favourite flavour ice cream. To make small, round balls of ice cream, fill a cup with boiling water and dip a teaspoon in the hot water, then drag across the top of the ice cream.
Once the profiteroles are filled with ice cream, place the lid on top, drizzle generously with the chocolate sauce and serve.