Soak currants, raisins, and sultanas in brandy, lemon, and orange juice overnight.

In a large bowl, combine soaked fruits (with any leftover liquid), suet, flour, sugar, salt, spices, mixed peel, breadcrumbs, grated apple, and eggs until well-mixed.

Grease a 2-pint pudding basin (or two 1-pint basins) and fill each basin about three-quarters full with the mixture.

Cover the pudding: Place a sheet of foil over a sheet of parchment paper, pleat the center, and wrap over the basin.

Tie tightly with string around the bowl, leaving extra string to create a handle for lifting.

Set a heatproof saucer upside-down in a large pot, place the pudding bowl on top, and fill the pot with water halfway up the bowl's side.

Steam for 8 hours, topping up the water as needed, then cool the pudding and rewrap with fresh parchment and foil.

Before serving, steam for 2 hours, unmold, and flame with brandy if desired. Serve with brandy butter, cream, or custard.