Preheat the oven to 180C/375F degrees.
Grease and line an 8 inch springform cake tin with parchment paper.
In a bowl, mix the erythritol and butter together until soft and blended.
Add the egg yolks and vanilla extract and stir thoroughly. Then add the pumpkin.
Add the coconut flour, pumpkin spices, salt, baking powder and beat until combined.
In another bowl, whisk the egg whites until stiff.
Gently fold the egg whites into the cake mixture.
Spoon half of the mixture into the baking tin and smooth evenly.