Preheat oven to 250C. With a serrated knife, cut the panettone into 3/4 to 1-inch dice.
For the eggnog custard, in a bowl thoroughly whisk together the eggs, yolks, sugar, milk, cream, rum, vanilla extract, and a healthy grating of fresh nutmeg. Add the bread cubes and mix well.
Spray a 6 hole, deep muffin tin with vegetable cooking spray. Ladle the bread/eggnog mixture gently and evenly into the muffin tins. Place the filled muffin tin into a tall sided roasting pan. Transfer to the preheated oven and carefully pour the hot water from kettle into the roasting tin pan, creating a water bath for the muffin tin to sit in.
Bake 15 to 20 minutes until the tops are nicely browned, and a toothpick comes clean from the center.
Bread pudding may be served warm or cold. Serve with freshly whipped cream and redcurrant and a dusting of icing sugar.