Preheat oven to 350 degrees F (180 degrees C).
In a bowl, add the Milk (2 1/4 cup) and Butter (2 tablespoon) and whisk. Take 3 tablespoons of the mixture in a smaller bowl, then add the Custard Powder (1 tablespoon).
Add the custard mix to the original bowl with the milk and butter and whisk together.
In another bowl, add the Egg (3), Granulated Sugar (1 cup), Ground Nutmeg (1/4 teaspoon) Ground Cinnamon (1/2 teaspoon), and Vanilla Extract (1 tablespoon) and whisk until it reaches a creamy texture.
Combine milk mixture and eggs mixture together and whisk well.
Rip the Bread (1 loaf) into 1 to 2-inch pieces.
Peel and slice the Banana (2).
In the bowl with the bread pieces, add the sliced banana and Raisins (1/3 cup). Pour in the liquid and mix well.
Cover the bowl and allow to rest for about 20 minutes for the bread to soak in the liquid.
Pour the bread mixture into an oven proof dish and place on the middle rack of your preheated oven for 50 minutes or until golden brown.
Serve with some warm Caramel Sauce (to taste).