Sprinkle the strawberries with the sugar and set aside for 2-4 hours.
Put the gelatine leaves into a small bowl of cold water and leave for five minutes until soft.
If using the powdered gelatine, stir into the very hot water until dissolved.
Pour 3 tbs of the Pimm's into a small saucepan and heat gently.
If using the gelatine leaves, squeeze the water from the gelatine and add to the hot Pimm's, whisking furiously until dissolved.
The procedure is the same for the powdered, except that you just stir the whole mixture in, including the water.
Set the Pimm's and gelatine mixture aside but keep warm.
Now, bring an inch or two of water to a bare simmer in a saucepan that will hold a large mixing bowl, without the bottom of the bowl touching the water.
Put the egg yolks and sugar into the mixing bowl, off the heat.
Use an electric beater to whisk for three minutes, until thick and pale.
Pour in the remaining Pimm's (not the gelatine mixture) and beat for another minute.
Put the bowl over the barely simmering water and beat continuously until the mixture has at least doubled and looks frothy, like the head on a glass of Guinness.
Take off the heat, pour in the gelatine mixture and beat for one minute.
Place the bowl in a sink of ice-cold water and cool for about 10 minutes, whisking occasionally.
Whip the cream into soft peaks and then whisk it into the zabaglione.
Spoon into four large wine glasses, leaving an inch at the top for the strawberries.
Cover and refrigerate for at least two hours.
Just before serving, spoon the strawberries and their juices into the top of the glasses.
