Prepare a 16 - 19 cm (6 1/2 - 7 1/2 inch) (1.5 litre (2 1/2 pint) souffle dish: cut a 58 x 25 cm (23 x 10 inch) strip of foil or greaseproof paper. Fold in half lengthways. Wrap the strip around the dish so it stands above the rim and secure with adhesive tape. Lightly oil inside of collar, above rim of dish.

Finely grate the zest from 3 limes;

squeeze the juice from all the limes and measure 100 ml (3 1/2 fl oz) for the souffle.

Sprinkle the gelatine over the water in a heatproof bowl. Leave to soak for 5 minutes until spongy, then set the bowl over a pan of simmering water and heat gently for 1 - 2 minutes until gelatine has dissolved, stirring occasionally. Remove gelatine liquid from heat and leave to cool slightly.

Meanwhile, put the egg yolks into a bowl with 200 g (7 oz) caster sugar, the lime zest and reserved juice. Using an electric whisk, beat until very pale, thick and creamy.

Whisk in the gelatine. Leave the mixture for 5-10 minutes, whisking occasionally, until it is beginning to thicken.

Meanwhile, whip the cream until standing in soft peaks.

In a clean, dry bowl, whisk the egg whites until standing in stiff peaks. Whisk in the remaining sugar, 1 tablespoon at a time, and continue whisking until meringue is firm and glossy.

Fold the whipped cream into the lime mixture, then gently fold in the meringue. Put half the mixture into another bowl and tint pale green with food colouring.

Put alternate spoonfuls of the 2 mixtures into prepared dish. Level the surface carefully, then chill for 4 hours, until set.

Remove tape from collar, then carefully peel away from souffle with the aid of a round-bladed knife. Press chopped nuts around the sides of the souffle. Serve as soon as possible.