Assemble the pudding:
Place the remaining bread pieces evenly in the heatproof pan on top of the hardened caramel. Pour the drained custard mixture over the bread, making sure all the bread is soaked.
Gently press the bread pieces so they soak up the custard.

Bake the pudding:
Preheat your oven to 350°F (175°C).
Cover the heatproof pan with aluminum foil.
Place the pan in a larger baking dish and carefully pour boiling water into the outer dish until it reaches halfway up the sides of the heatproof pan. This double boiler method helps the pudding cook evenly.
Bake in the preheated oven for about 45 to 50 minutes or until the pudding is set and the top is lightly browned.

Serving:
Allow the pudding to cool slightly before serving. You can serve it warm or chill it in the fridge to serve it cold.
The caramel will have melted under the bread, forming a sweet, gooey layer that complements the soft, custard-soaked bread perfectly.