Heat your oven to 180°C/160°C Fan/Gas mark/355°F
Line your square 9"x 9" tin with greaseproof (parchment) paper. The easiest way to do this is to lie one piece over the sides and base one way and then another piece the other way.
Add your sugar to your large mixing bowl and rub any large lumps between your fingers to remove them.
Sift over your flour, bicarbonate of soda (baking soda), salt, cinnamon, ginger and nutmeg and mix together.
Add your oil and mix together until clumping.
Add your lightly beaten egg and beat on a low setting until incorporated.
Beat on a medium-high setting for 10-15 seconds, wiping down with your spatula in-between to ensure all the ingredients are mixed in.
Gentle fold in your grated pumpkin.
Pour into your prepared tin and bake for about 40-45 minutes until a skewer or cocktail stick inserted into the centre of the cake comes out clean.
Leave to cool in the tin for 10 minutes and then invert onto a cooling rack, ensure fully cooled before adding your icing.