1 cup sugar
2/3 cup canned pumpkin
1 teaspoon lemon juice
3/4 cup all purpose flour
1/2 teaspoon ground ginger
1/2 teaspoon freshly ground nutmeg
2 teaspoons ground cinnamon
1/2 teaspoon salt
1 teaspoon baking powder
1 cup walnuts, finely chopped
1 1/4 cups powdered sugar, plus additional for sprinkling
1 (8 ounce) package cream cheese, softened
1/2 cup butter, softened
1/2 teaspoon vanilla extract
Preheat oven to 350 degrees F. Prepare a 17 1/2 x 12 1/2 jellyroll pan with cooking spray, then line with parchment paper. Spray the top of the parchment paper with cooking spray.
With an electric mixer, beat the eggs, sugar, pumpkin, and lemon juice until smooth. In a separate bowl, sift together the flour, ginger, nutmeg, cinnamon, salt, and baking powder. Add the flour mixture to the egg mixture and mix until combined. Spread the batter evenly in the prepared pan. Sprinkle the batter with the chopped walnuts. Bake in preheated oven for 14 minutes. Let cake cool in pan for 5 minutes, then invert cake onto a wire rack. Spread a large tea towel out flat and sprinkle with powdered sugar. Carefully transfer the cake to the towel, folding in the sides of the towel over cake. Beginning on one of the short sides of the cake, roll the cake up in the towel and cool in the refrigerator for about 45 minutes.
Using an electric mixer, beat powdered sugar together with cream cheese, butter, and vanilla until smooth. Carefully unroll the cake and spread the cream cheese mixture evenly over the cake. Gently re-roll the cake and refrigerate. Dust with powdered sugar just before slicing and serving.