Zest the oranges and set the fruit aside.
Infuse milk, cream, zest, vanilla, and cardamom by bringing to a boil then resting for one hour.
Preheat the oven to 180°C and warm a large roasting tin inside.
Butter the bread slices and cut them into triangles.
Segment the oranges, removing all skin and peel, and slice segments in half.
Whisk eggs and sugar together, then strain the infused milk into the mixture.
Layer bread, pistachios, sultanas, and orange segments in the dish, ending with a neat bread layer.
Pour the custard mixture over the layers and boil a kettle of water.
Place the dish in the roasting tin and fill the tin halfway with boiling water.
Bake for 30-40 minutes until nearly set.
Glaze the top with heated marmalade and serve with icing sugar and crème fraîche.