Core pumpkins with a spoon.
Heat half the butter in a pan. Slice mushrooms and saute in butter. Mix sugar with remaining melted butter and season with salt, nutmeg, cinnamon and cloves.
Rub inner walls of pumpkins with butter-spice mixture and maple syrup. Add mushrooms to pumpkins. Cut bacon into strips and add to pumpkins. Place pumpkins in a baking dish and surround with herbs and onions cut into quarters. Pour hot water into baking dish until 3 cm (approximately 1 inch) in height and bake in a preheated oven at 200°C (approximately 400°F) for 40 minutes. Serve warm.