Add all the pumpkin batter ingredients plus the whisky that the raisins haven’t soaked in to your food processor or blender
. Once smooth, add a quarter to the baking dish. Top with a third of the bread. Repeat until all the batter and all the bread have been used. Make sure the bread is well coated (you can also drop the bread along with the raisins into the blender to make sure it’s well coated). Distribute the raisins throughout the casserole. Cover and refrigerate overnight (or at least an hour or two).