Fill a large bowl with ice and a little water.
Place the cream and ginger into a saucepan and bring to the boil.
Remove the saucepan from the heat and cover, leaving the cream to infuse for 30 minutes.
After 30 minutes return the pan to the heat and bring back to the boil.
Place the egg yolks and sugar in a bowl and whisk together.
Pour in some of the hot cream mixture into the egg yolks and whisk continuously to combine.
Pour the egg yolk mixture into the saucepan containing the rest of the cream and continue cooking gently for 3-4 minutes, or until the mixture coats the back of a spoon.
Add the butternut squash to the cream mixture and, stir in throughly.
Place the saucepan into the iced water bath, stirring occasionally, until chilled.
Add the lemon juice to the cream and strain through a fine-mesh sieve.
Pour the mixture into an ice cream machine and churn until smooth. Keep frozen until ready to use.