Pre-heat the oven to 180 C. Beat the eggs and butter together in a large mixing bowl with a hand held electric mixer or in a free standing mixer.
Mix the dry ingredients together in another bowl before adding to the eggs and mixing together well. Add the grated pumpkin and mix again thoroughly. Simples.
Pour the batter into a greased and lined baking tray. I use bakoglide. Mine measured 20 cm by 30 cm. Bake for 45 mins until springy to the touch and an inserted skewer comes out clean.
Leave to cool for ten mins in the tin before removing to a wire rack to completely cool.
Add all the ingredients to a food processor and whizz together. If you don't have a food processor then sieve your icing sugar onto the butter and cream cheese and beat well to combine to a smooth paste.
Using a palette knife spread the icing all over the cake. Using a ruler or just your eye if you're confident cut up into squares. Decorate with fudge chunks or whatever scary sprinkles you can find for Halloween.