Beat eggs on high speed of mixer for 5 minutes; gradually beat in sugar. Stir in pumpkin and lemon juice. Stir together flour, baking powder, cinnamon, nutmeg and salt. Fold into pumpkin mixture.
Spread into greased and floured 15x10x1 inch pan. top with chopped nuts. Bake at 375 degrees for 15 minutes. (I baked at 350 degrees because I was using a dark non-stick surface baking pan lined with greased and floured parchment paper. The cake is easier to get out of the pan.)
While still warm turn out onto towel sprinkled with powdered sugar and roll starting at narrow end (roll towel and cake together). Cool.
Combine all ingredients for cake and beat smooth. Unroll cake, spread with filling. Reroll cake and chill. Optional: Sprinkle finished cake with powdered sugar.