Beat the butter and sugar until light and fluffy, then beat in the eggs, then mix in everything else apart from the flour.
Once mixed, lightly fold in the flour and then scrape into a well greased pudding basin. Take a piece of baking parchment and grease one side to cover the pudding, then cover with a larger piece of foil (not too tight) and secure with an elastic band or string.
Lower onto the trivet inside the Instant Pot and pour boiling water to about an inch below the rim of the pudding basin.
Put the lid on and leave the steam release valve Venting. Set to Steam and begin the timer for 15 minutes as soon as you hear steam coming out the pot. (Note that as the pot is not steaming under pressure when the vent is open, it will not start its own timer countdown)
When the 15 minutes is up, change the steam release to Sealing, select Manual High Pressure and set for 45 minutes, followed by 15 minutes Natural Pressure Release.
Carefully remove the pudding from the pot and allow to cool completely, then dry the top of the pudding with kitchen roll and re-cover with fresh paper and foil, and store in a cool dark place until required.
To cook on Christmas Day:
When ready to cook, place the pudding on the trivet in the Instant Pot and pour boiling water up to one inch below the rim of your basin.
Put the steam release to Sealing, and select the Steam function. Set the time for 40 minutes, followed by Quick Pressure Release.
Invert onto a plate, slice and serve with rum or brandy butter, custard or cream.
NOTE: Soak the dried fruit in Frangelico for at least 24hrs before you begin.