Preheat oven to 375*F.  Butter 10x15 inch jelly roll pan and line with parchment paper. Butter parchment paper.

Sift together flour, spices, and salt.  Set aside.

Beat eggs with an electric mixer, slowly adding sugar until light and fluffy.  Whisk in brown sugar, vanilla, and molasses, continuing to beat until the mixture becomes thick and creamy, about 3 minutes.  Fold in flour mixture with a rubber spatula until combined and no white streaks remain.  Spread batter evenly into prepared pan. Tap gently on the counter to allow the mixture to settle.

Bake in preheated oven 16-18 minutes, until cake bozs back when lightly touched.

While cake is baking, lay out a large tea towel on a flat surface. Dust lightly with 1/4 cup powdered sugar. Tip the baked cake onto the dusted tea towel as soon as it comes out of the oven and carefully peel off the paper.  Dust with remaining 1/4 cup powdered sugar. Make a tiny cut along the width of cake at one narrow edge about 1 inch in. Using the tea towel as a lever and beginning at that end, gently roll up the cake tightly, with towel inside. Place onto a wire rack to cool completely.

Place whipping cream into a chilled mixer bowl.  Beat in electric mixer until it doubles in volume and starts to form soft peaks.  Fold in lemon curd; mixture will continue to thicken.

Carefully unroll cooled cake and spread completely with lemon cream.  Carefully reroll.  Trim off ends and place onto a serving plate.  Dust with additional powdered sugar.  Keep covered in the refrigerator until ready to serve, then cut into slices.