Preheat oven to 200°c. Working in upward brushstrokes from the bottom to the top of each ramekin brush 6 x 200ml ramekins with melted butter, then liberally dust with extra caster sugar, gently tapping ramekins to remove excess sugar.

Process raspberries in a food processor, then press through a sieve, discarding solids, to give 1 cup puree. Add 1 tbs caster sugar and stir until sugar dissolves.

Using electric beaters, whisk egg whites to soft peaks. Whisking constantly, slowly add remaining ¼ c caster sugar and the remaining egg white mixture.

Using a piping bag, if possible, pipe raspberry mixture to half-fill the ramekins. Add a truffle to each one, then pipe raspberry mixture on top to fill to the rim of the ramekin. Smooth top with a palette knife, then run your thumb gently around the inside of the ramekins (this will help the soufflés to rise.)

Bake for 7 minutes or until well risen and golden on top

Serve soufflés dusted with icing sugar and topped with chocolate curls.