Preheat oven to 180 C / Gas 4. Grease 12 muffin cups or line with paper muffin cases.
Split pumpkin in half. Remove seeds and strings. Place on baking tray, cut side down. Cover with foil and bake in preheated oven until tender, about 90 minutes. Scoop out pumpkin and puree in blender. Weigh out 500g of pumpkin puree; set aside.
In a large bowl, stir together flour, sugar, bicarb, baking powder, cloves, cinnamon, nutmeg, allspice and salt. In a separate bowl, beat together the 500g pumpkin puree, vegetable oil and eggs. Stir pumpkin mixture into flour mixture until smooth. Scoop muffin mixture into prepared muffin cups.
Bake in preheated oven for 20 to 25 minutes, until a skewer inserted into the centre of a muffin comes out clean.
Enjoy warm with ice cream or cold with cream and a nice cup of tea!