Preheat oven to 375 degrees. Butter an 8 or 9 inch springform pan. Sprinkle with sugar to coat bottom and sides.
Beat sugar with egg yolks in a stand mixer until light and fluffy, about 10 minutes.
Add vanilla and beat well to incorporate. Transfer sugar-yolk mixture to a large bowl.
Clean mixer bowl. Add egg whites and beat until soft peaks form. Add salt and continue beating until whites hold their shape. Do not overbeat.
Fold whipped egg whites into sugar-yolk mixture.
Fold in ground pistachios.
Pour into prepared pan and bake for 30 minutes or until golden on top and a toothpick inserted into center of cake comes out clean.
Let cool, then invert onto platter. Dust with powdered sugar and serve with ice cream or whipped cream.