Preheat oven to 375 degrees F.
Line a 15x10 inch baking pan with parchment paper. Grease and flour the pan and the top of the paper.
In a large bowl, beat egg yolks until think. Gradually add 1/2 cup sugar and the pumpkin. Beat mixture until the sugar is almost dissolved.
In a smaller bowl, beat egg whites until soft peaks form. Gradually add remaining sugar and beat until stiff peaks form. Fold the egg whites into the pumpkin mixture.
In a smaller bowl, sift together flour, baking soda, cinnamon, and salt. Gently fold into pumpkin mixture. Spread into pan.
Bake at 375 degrees F for 13 to 15 minutes, or until cake springs back when touched. Cool 5 minutes and turn cake onto a kitchen towel sprinkled with powder sugar. Gently peel off paper.
Roll up cake in in the towel starting with the shorter side. Cool completely before adding the filling.