Preheat the oven to 160C/310F/Gas 2.
For the pudding, pour the milk and cream into a pan and add the split vanilla pod. Bring slowly to the boil over a medium heat.
Place the sugar into a large bowl with the egg yolks and whisk until the mixture is light and creamy.
Slowly pour the egg mixture into the hot milk and cream, whisking all the time, then add the breadcrumbs and lemon zest.
Half-fill a roasting tin with boiling water to make a bain-marie. Pour the pudding mixture into individual ramekins and place them into the bain-marie.
Place the bain-marie in the centre of the oven and bake for 10-15 minutes, or until the puddings are almost set but still slightly wobbly in the centre.
Remove from the oven and allow to cool.
Increase the oven temperature to 190C/375F/Gas 5.
For the meringue topping, place the egg whites into a large clean bowl and whisk until stiff peaks form when the whisk is removed. Gradually whisk in the caster sugar, a tablespoonful at a time.
Place the jam into a small pan over a low heat and gently melt. Spread the jam over the top of the puddings, then cover the puddings completely with the meringue mixture.
Sprinkle with the icing sugar and bake for 8-10 minutes, or until the top is crisp and lightly browned.
To serve, remove from the oven and serve immediately.