Preheat the oven to 180°C.
Roast halved pumpkin at 180°C for 45 minutes, cool, and mash flesh into smooth purée.
Grease and flour a 21cm bundt tin.
Beat sugar, pumpkin purée, cider, and oil together, then incorporate eggs one by one.
Sift dry ingredients and beat into the wet mixture for 3 minutes until smooth.
Bake 550g of batter in the tin for 35 minutes until a skewer comes out clean.
Cool the first cake for 5 minutes, turn out, then repeat the process for the second half.
Beat butter, cream cheese, and icing sugar together until smooth to make the icing.
Flatten the bottoms of both cooled cakes and align them to form a pumpkin shape.
Sandwich cakes with icing, fill the center hole, top with remaining icing, and add a fondant stem.