Preheat the oven to 180C/350F and line a 20 cm or 8 inch round cake tin with parchment paper.
Place the butter and sugars into a bowl and beat on medium until pale and well combined, approximately 3 minutes.
Add in the egg yolks and whip until well combined, a further 1 minute.
Add in the pumpkin and combine until the mixture is smooth.
Sift the flour, baking powder, baking soda and salt into the bowl and beat on low until just combined.
In a separate bowl, whip the egg whites until soft peaks form.
Add the whipped egg whites to the cake batter and gently fold the until it is a smooth mixture and fully incorporated.
Spoon the batter into your cake tin smooth out evenly.
Bake for 40 minutes until golden and a skewer comes out clean.