1. Preheat oven to 375 and line a 15X10 pan with parchment paper.
2. Put the eggs in a large bowl and beat with a mixer on high speed for 4 minutes.
3. Gradually add the sugar while still beating the egg whites.
4. Blend the pumpkin puree and lemon juice using a rubber spatula.
5. In a separate bowl sift together the flour, baking powder, cinnamon, ginger, nutmeg and salt.
6. Mix the dry ingredients into the pumpkin mixture until blended together well.
7. Spread the batter evenly over the parchment paper.
8. Bake in a 375 degree oven 12 minutes or until a knife inserted in the center comes out clean.
9. Turn the cake out onto a flat surface like a cutting board and sprinkle completely on top with the powdered sugar.
10. Beat the cream cheese, butter and vanilla together until light and fluffy.
11. Carefully unroll the cake and spread the mixture evenly over the cake.
12. Sprinkle the nuts over the filling.
13. Roll the cake up again, sprinkle the outside again with powdered sugar and place in the refrigerator for 2 hours or until completely chilled.
14. Cut into 1 1/2 inch slices and serve.