Preheat oven to 160'
Whisk eggs, sugar, vanilla and cream until well combined.
Cut croissants into 3 or 4 slices.
Smear jam across bottom of baking dish and a layer of rhubarb slices.
Arrange croissant pieces in dish and pour custard mix over.
Push in remaining rhubarb slices and rest in the fridge for an hour (this helps the croissants to soak up custard mix).
Sprinkle sugar over the top and bake until custard has just set (a little runny is good, as it will continue to cook and set while cooling down).
Serve warm with a dollop of cream.
