Fill a large stockpot with one or two inches (2½-5cm) of water and set a steamer basket on top. Generously butter a 1-liter pudding bowl or ½ sized bundt pan. Set aside.
In a large mixing bowl, combine the brown sugar, molasses, and eggs.
In a separate bowl, combine the breadcrumbs, flour, cinnamon, baking soda, nutmeg and salt, and then add this mixture to your brown sugar mixture and stir to combine.
Fold in the grated butter, carrots, and raisins, and then transfer the batter to your prepared pudding bowl.
Place a circle of parchment paper directly on top of the batter, and then cover the bowl with foil. Set the bowl on the steamer basket, put a lid on the pot and turn the stove on to medium-low. Keep a kettle with hot water nearby.
Steam the pudding for about 1½ hours or until firm to the touch. Check and replenish the steaming water with the hot water from the kettle every 25-30 minutes. (Check out 'How to Steam A Pudding' for step by step instructions)
Carefully remove the pudding from the pot and let cool for 10 minutes before unmolding onto a serving platter. Serve warm with a side of creme Anglaise.
Store leftover pudding in an airtight container at room temperature for up to three days or freeze for up to two months. Microwave or steam briefly to reheat.