Put the cream in a pan and heat gently until just comes to the boil.
In a bowl, beat the eggs, caster sugar and vanilla until creamy.
Pour the warm cream gradually over the egg mixture, while stirring constantly until you get a smooth, thick cream.
Grease a baking dish with butter.
Cut the croissants into 3cm thick slices, then spread some mincemeat on them.
Arrange the croissants in the baking dish, letting them overlap each other.
Scatter the chestnut and fig bits on top, tucking them between the slices. Pour the custard over the croissants.
Let it rest for 10 mins, while you preheat the oven to 180°C.
You can sprinkle some muscovado sugar over the croissants, if you want a crunchy, caramelised crust, then bake for 35-40 mins in the middle of the oven.
Whet the top is golden and the custard has just set (should still wobble), then it's ready to serve.