To make the choux pastry, place the water and butter into a pan and heat gently until the butter has melted. Turn up the heat and quickly add the flour and salt. Remove from the heat and beat vigorously until a smooth paste is formed. Place into a mixer with a K attachment, beat to cool then add the eggs, one at a time. Spoon into a piping bag.
Line a large baking sheet with parchment or greaseproof paper then pipe a large circle of pastry on top. Bake for 30 minutes, until golden brown then cool.
Meanwhile make the raspberry sauce: tip the raspberries and sugar into a blender with 50ml water and purée until smooth. Place a sieve over a bowl and pour the blended purée through. Use a spatula to press the sauce through if necessary.
Add vanilla to the cream and whip until soft peaks form. Slice the choux circle in half and remove the top. Pipe or spread whipped cream over the bottom half, next add berries then drizzle with raspberry sauce. Replace the top half of the choux, dust with icing sugar and serve.