1. In a large bowl, combine the vanilla seeds, sugar, lemon zest and cornflour, then whisk in the egg yolks.

2. In a medium pot, add the milk, cream and vanilla pod and simmer over medium heat for 2 minutes.

3. Remove the vanilla pod and pour the liquid over the egg mix, whisking as you pour until amalgamated.

4. Pour the custard back into the pot and cook over medium heat, just until it starts to bubble, stirring or whisking constantly to ensure it doesn't stick to the bottom. Once the custard is thick and free of lumps, pour into a jug and serve. You can also refrigerate and serve cold. The custard will keep for three or four days.

Tip: this custard is particularly good with these roasted pears.