To make the parfait

1. Using a stand mixer or electric beater, beat the egg yolks and icing sugar until they are light and fluffy and pale in colour.
2. Add the salt, vermouth and vanilla and briefly mix together to combine.
3. In a separate bowl, whip the cream until it forms soft peaks. It should be thick and airy, but still pourable.
4. Slowly fold the egg mixture into the cream until combined.
5. Pour into a loaf tin or similar dish lined with baking paper and set in the freezer for at least 6 hours.

To make the plum compote

1. Heat the plums with the lemon juice and peel, bay leaf and star anise in a saucepan over medium heat.
2. Simmer until the plums begin to fall apart and the liquid is a syrupy consistency. 
3. Remove the bay leaf, star anise and lemon peel, then let the compote cool before refrigerating.

To serve

Depending on the temperature of your freezer, you may need to pull the parfait out a few minutes before serving to let it soften. Slice the parfait then top each serving with some of the compote.

Optional: Garnish with some slices of freeze-dried plum.