8 cups pumpkin puree
4 cups sugar
1.5 teaspoons cinnamon
1/2 teaspoon nutmeg
1 teaspoon ginger
1/4 teaspoon ground cloves
1 teaspoon ground cardamom
1 packet vanilla sugar
juice and zest of 4 lemons
Peel the pumpkin, slice it, wrap it in foil, and bake it in the oven until soft, then blend it until smooth. Alternatively, you can cut the pumpkin into pieces with the skin on, place them in a dish with 1 inch of hot water, skin side down, cover with a lid, and microwave for 15 minutes. Scoop out the flesh with a spoon and mash it.
Mix all the ingredients together and transfer to a heavy-bottomed pot. Cover with a lid, place in a preheated oven at a low temperature of about 150°F, and bake for 3 hours until it turns into a thick, brownish, homogeneous mass, stirring occasionally to prevent burning.
Fill sterilized jars with the mixture and seal with lids. This is a favorite jam among the English, often described as a taste of childhood, and it truly has a delicate flavor with a hint of tartness and an unforgettable aroma, not to mention how healthy it is.