Dice the pumpkin and boil it in a small saucepan of water until it is tender.

Mash the pumpkin and butter together in a large bowl and allow that to cool fully.

Preheat your oven to 160 degrees celsius and line a round cake pan (approx 23 cm diameter) with baking paper.Add the sugar, eggs and sweetened condensed milk to your pumpkin and butter. Mix until everything is well combined.

Add the remaining cake ingredients to your bowl and mix until the batter has just combined.

Pour the cake batter into your prepared cake pan and bake for 40 minutes or until it is baked through.

Allow your cake to cool fully before frosting with the spiced brown sugar frosting.

Place your butter, brown sugar, spices and water into a small saucepan. Heat on low, stirring occasionally until the sugar is dissolved.

Pour into a medium sized bowl, cool for 20 minutes or until the mixture is only a little bit warm to the touch. Add your cream, use an electric beater to whisk everything together until it is all well combined. Add half of your icing sugar to your bowl, whisk well before adding in the remaining icing sugar. Whisk well, until the frosting is thick and smooth.

Frost your cake with your prepared frosting. Work quickly as this frosting will set quickly. Decorate with walnuts if desired.