Preheat the oven to 350 degrees F (175 degrees C). Put torn French bread into a bowl. Mix milk and pumpkin puree together in a separate bowl and pour over French bread. Let soak until moistened, about 5 minutes. Mix sugar, eggs, vanilla extract, orange flavoring, and pumpkin pie spice together in a bowl. Pour into bread mixture and stir. Fold in pecans and raisins. Place butter in a 9x13-inch baking pan and put into the preheated oven, about 5 minutes. Remove pan from oven when butter has melted and spoon in bread mixture. Bake in the hot oven until pudding is firm in the middle and edges are brown and crisp, 35 to 45 minutes.