In a large mixing bowl, beat eggs on high speed for 5 minutes; gradually beat in sugar. Stir in pumpkin and lemon juice.
In a small bowl, sift together flour, cinnamon, baking powder, ginger, salt and nutmeg. Fold into pumpkin mixture. Spread batter in a greased and floured 15X10X1 inch jelly roll pan. Sprinkle with walnuts.
Bake at 375 for 15 minutes. Immediately invert cake onto a dish towel sprinkled with powered sugar. Roll up cake and towel, jelly roll style, starting from the short side. Cool completely. Unroll cake and spread filling, re-roll and chill.
Helpful Hint: use wax paper on bottom of jelly roll pan and peel wax paper from cake.