How to make Colm O'Gorman's seasonal baked apples - with hazelnut crumble and vanilla custard

Baked apples with crumbles and custard - a seasonal favourite
Autumn is perhaps my favourite season. I adore it. When the leaves start to fall and the days get shorter, I reach for familiar comforts.
I love its bright sunny days when the air is cold and crisp, and my breath freezes as it leaves my lungs.