1. Heat your oven to 180C (200C conventional). Place the pumpkin on a roasting tray and roast for 90 minutes (there's no need to season it or add oil). Scoop out and discard the seeds, then scoop out the flesh. Set aside 1 cup of flesh to cool to room temperature.

2. Heat your oven to 160C (180C conventional). Grease and line a 20cm square cake tin. Cream the butter, brown sugar and vanilla together until fluffy. Beat in the eggs and milk a little at a time until combined. Sift the flour, baking powder and cinnamon together and fold into the wet ingredients including the cooled cooked pumpkin to create a smooth batter. Pour the batter into the cake tin and bake for 30-40 minutes until a skewer inserted into the cake comes out clean. 

3. While the cake is baking, combine the ingredients for the butterscotch sauce plus a pinch of salt and bring to the boil. When the cake is cooked, remove it from the oven and immediately prick it all over with the skewer. Pour over a third of the hot butterscotch sauce and allow it to stand for at least 20 minutes so the sauce can soak into the pudding. Return the remaining sauce to the stove and boil it again to reduce it slightly.

4. Serve the pudding with the rest of the sauce and vanilla ice-cream.

Adam's tip The skin of pumpkin is entirely edible so save yourself a lot of hassle (and potential injury) by defaulting to skin-on when cooking them. If it's a little tough, it's easier to remove once cooked.

Also try Adam Liaw's rigatoni with pumpkin cream, rosemary and bacon