Mix the double cream and caster sugar in a saucepan. Bring to the boil, and reduce to a simmer for a couple of minutes. Then remove from the heat
Pour in the lemon juice, and sieve the mixture and pour into the serving glasses, allow to cool fully on the side before placing in the fridge to set.
Preheat the oven to 140Â°C
To make the biscotti, mix the egg, plain flour, ground ginger and caster sugar in bowl until it forms a strong dough. Then roll the dough into a sausage about 4-5cm thick and place on a baking sheet.
Bake in the oven for 35 minutes. Then remove from the oven and slice the baked dough into 2cm thick pieces. Place back in the oven sliced for another 10 minutes. Once cooked, place on a wired rack to cool.
To serve, sprinkle lemon zest over the top and serve with a ginger biscotti.