Prepare the barbecue for indirect cooking over medium to low heat (as close to 180°C as possible). If using a Weber Q barbecue, set up your barbecue with a convection tray and a trivet.
Lay the croissants in a Weber large casserole dish.
In a large jug, mix together the eggs, cream, milk, cinnamon, vanilla, nutmeg, rum and sugar. Pour mixture over the croissants. Using a spoon, press the croissants into the liquid. Scatter the raspberries on top.
Bake the pudding over indirect medium-low heat, without the casserole dish lid, for 30 to 40 minutes or until golden and just cooked through.
Remove the pudding from the barbecue, dust with icing sugar and serve with cream or ice cream.