Preheat oven to 375 degrees F. Prepare an 11x17” sheet pan with a buttered sheet of parchment paper. Sprinkle water on pan to help hold paper in place.
Beat egg whites to soft peaks and set aside.
In a separate bowl whip the yolks and sugar to peaks, then add flour and mix well. Fold in the whites gently.
Spread mixture onto parchment in a rectangle ½” thick with an off-set spatula. Bake 8-10 minutes or golden brown in color.
While the cake is baking, whip cream with powdered sugar and vanilla until stiff.
Allow cake to cool a bit and remove parchment before spreading the whipped cream to the edges.
Cake can be rolled into a jelly roll, but it’s traditional to fold into thirds length-wise. Chill at least 3 hours to set.
Cut into slices or pie shaped wedges to serve. Dust with powdered sugar or cocoa to garnish. Enjoy!