Pumpkin and Pistachio Cake

Preheat oven to 180°C (approximately 350°F).

Finely grate pumpkin pulp. Stir egg yolks with 1/3 of the sugar, salt and lemon zest until fluffy. Beat egg whites until stiff, sprinkle with remaining sugar and beat until glossy and cut resistant. Mix grated hazelnuts with flour and add pumpkin. Fold 1/3 of egg white mixture into egg yolk mixture and mix well. Then fold in remaining egg whites and add pumpkin mixture. Fold together gently with a wooden spoon. Add pistachios. Line bottom of a springform pan with parchment paper and pour in dough. Smooth and bake for 50 minutes. Cool overnight in pan.