I could tell you ...
... but, as it's my own secret recipe, I'd then have to kill you.
Actually it's a version of a Rich Fruit Cake.
A typical recipe can be found here. But, as I say, I've adapted it for my own use. In particular, I have used different spices to give it a seasonal flavour.
A rich fruit cake only improves with age. It will be wrapped in baking parchment and tinfoil, and unwrapped at weekly intervals and a dessert spoonful of Irish Whiskey carefully poured over to soak into it. About a week before Christmas, I'll cover it in marzipan (almond paste) and then ice it a few days before the big day.