Frozen raspberries are actually better than fresh for the pureé (or coulis) which is used as the base of this soufflé. They contain more moisture than fresh, and are much cheaper.
50g/2 oz unsalted butter
220g/734oz caster sugar
16 fresh raspberries
100ml/312fl oz Framboise (raspberry eau de vie)
12 egg whites
200ml/7fl oz raspberry reduction (see basic recipes on page 54)
To serve: 1 quantity raspberry pureé, made with 300g/11oz raspberries and 100g/4oz caster sugar, blended and sieved.
Preheat the oven to 180C/350F/Gas 4 and thoroughly grease four soufflé dishes 7.5cm/3in in diameter and 6.25cm/212in deep with half the butter. Place in the fridge until the butter sets hard, then butter again just before pouring in the soufflé mixture. Sprinkle with 20g/34oz of the caster sugar to coat, tipping out any excess. [See my comments on lining the dish]
Marinate the fresh raspberries in the Framboise until ready to use.
Put the egg whites into the bowl of your mixer and begin to beat. When they start to take shape, start adding the remaining sugar, a quarter at a time. When thoroughly mixed in, add another quarter and so on. [You can check whether the sugar has fully dissolved by rubbing a tiny bit between you fingers - if it's still grainy - it hasn't fully dissolved]
Put the raspberry reduction (the soufflé base) in a round bowl and whisk in a third of the beaten egg white; this loosens the base. Fold in the remaining egg white carefully.
Half fill the soufflé dishes with the mixture, then place three drained, marinated raspberries in the centre. Fill to the top with the mixture, then scrape off evenly with a palette knife. Run your finger around the edge to push the mixture away from the sides. Cook in the oven for 10 minutes. [Running your fingernail around the edge should create a lip, which allows the soufflé a clean lift from the dish]
To serve, place the dish on a plate with a raspberry on top, and some of the pre-prepared raspberry puree, or coulis, on the side.