1Preheat oven to 350 degrees. Line bottom of a 17 1/2 by 11 1/2 inch jelly roll pan with aluminum foil leaving a 2-inch overhang on the short ends. Fold overhang underneath pan. Butter aluminum foil and sides of pan. Lightly dust bottom and sides of pan with flour. Tap out excess. Sift together flour, baking powder, cinnamon, ginger, salt and nutmeg. In a stand mixer beat eggs until frothy. Add sugar in slow stream. Continue beating for 10-12 minutes or until mixture has tripled in volume and batter is pale yellow and forms thick ribbons when beaters are lifted. Beat in vanilla, lemon juice. Fold in pumpkin.
2Resift half of the flour mixture over batter. Using a large spatula fold the flour mixture into batter making sure to bring spatula to bottom bowl to free any flour that may be clinging to the bottom and side of bowl. Resift remaining flour mixture over the batter and fold it in. Scrap batter into prepared pan and spread it evenly with a spatula. Bake sponge cake for 15-18 minutes or until the center of cake springs back when pressed gently. Run top of a knife around edges of pan. Lightly dust a clean kitchen towel with confectionery sugar. Invert cake onto towel and remove pan. Carefully peel off foil. Starting at long side roll cake and towel together into a tight cylinder. Cool on wire rack.
3To prepare filling, beat cream cheese, butter and confectioners' sugar for 8-10 minutes on medium-high speed. Beat in vanilla. To assemble cake carefully unroll cake. Spread filling over cake. Reroll cake (not in towel this time) into a tight cylinder. Wrap the roll in a piece of aluminum foil. Twist ends of foil to secure the round shape of roll. Refrigerate over night. Cut into 1/2 inch slices and top with whipped cream.