• Grease a 15x10x1 inch baking pan.
• Line the bottom of the pan with parchment paper, grease the top of the paper and set aside.
• Preheat the oven to 375*F.
• In a small bowl, stir together the flour, baking powder, cinnamon, ginger, nutmeg, salt and set aside.
• In a large mixing bowl beat the eggs on high speed for about 5 minutes until thickened.
• Lower to medium speed and gradually add the sugar, beating until it is light in colour and fluffy.
• Stir in the pumpkin and the lemon juice.
• Next, beat in the flour mixture just until combined.
• Spread the batter evenly in the prepared baking pan using an offset spatula.
• Sprinkle the finely chopped walnuts evenly over the batter.
• Bake in the preheated oven for about 12 minutes or until the cake springs back when touched.
• Meanwhile, lay out a clean kitchen towel and sprinkle generously with icing sugar. (This will ensure that the cake does not stick to the dish towel and will give the cake a pretty appearance.)
• When the cake is done, immediately loosen the edges with a knife and invert it onto the clean kitchen towel (nuts side down) and peel off the parchment paper.
• Starting at the short end, roll the cake in the towel and transfer to a wire rack and cool for 30 minutes to set the shape.

Cream Cheese Frosting

• For the filling, in a medium mixing bowl, beat the cream cheese, butter and vanilla on medium speed until it is smooth and then gradually beat in the powdered sugar.
• Unroll the cake and spread the filling in a thin layer within 1 inch of the borders.
• Firmly roll up the cake using the towel to help if needed.
• Cover the pumpkin cake roll and chill for 4 to 48 hours.
• When ready to serve, trim off edges and dust with powdered sugar.
• Slice into equal portions and enjoy.