Line a greased 15 x 10 inch jellyroll pan with waxed paper; grease and flour wax paper. Set pan aside.
Beat egg yolks at high speed with an electric mixer until thick and pale. Gradually add butter and molasses, beating until blended.
Beat egg whites at high speed until foamy. Gradually add sugar, 1 tbls. at a time, beating until stiff peaks form and sugar dissolves (2-4 minutes). Fold egg whites into yolk mixture.
Combine flour and next 6 ingredients; gradually fold flour mixture into egg mixture. Spread batterevenly into prepared pan. Bake at 350F for 8-10 minutes or just until cake springs back when touched lightly.
Sift powdered sugar in a 15 x 10 inch rectangle on a cloth towel. When cake is done, immediately loosen from sides of pan, and turn out onto sugared towel. Peel off wax paper. Starting at narrow end, roll up cake and towel together; cool completly on a wire rack, seam side down.
Unroll cake; spread with half of Spiced Cream Frosting' carefully re-roll. Place on a serving plate, seam side down. Spread remaining Spiced Cream Frosting on all sides. Pull a fork or an icing comb down length of frosting. Cover loosely, and chill until ready to serve.
Combine all ingredients; beat at medium speed until soft peaks form.