Preheat oven to 375°F.
In the bowl of a stand mixer, beat the eggs for 5 minutes, then gradually add sugar. Stir in the pumpkin and lemon juice until well blended.
In a medium size bowl, mix together the flour, baking powder, cinnamon, ginger, nutmeg and salt. Fold into the pumpkin mixture until just blended. Take care not to over mix the batter so it stays light.
Spread the mixture onto a 10x15-inch baking sheet or jelly roll pan lined with parchment paper, leaving a ½ inch space from the sides of the pan. Top the pumpkin mixture with the chopped nuts if desired.
Bake for 12-15 minutes. Use a paring knife around the edges of the cake to to loosen it from the pan.
Generously sift powdered sugar on a clean, fine napped dish cloth or flour sack. After removing the pumpkin cake from the oven, immediately invert onto the powdered sugar covered dish cloth. Sprinkle with more powdered sugar and roll the cake up in the dish towel. Allow to cool completely.
While the cake is cooling, make the frosting. Mix the powdered sugar, cream cheese, butter and vanilla in a small bowl until smooth. Once the cake has cooled, gently unroll it. Spread the cream cheese mixture evenly over the cake. Roll up again and chill. Slice into pieces and serve or freeze.