Make the cake: Preheat the oven to 375 degrees F. Coat an 11-by-17-inch rimmed baking sheet or jelly roll pan with cooking spray; line the bottom with parchment paper. Whisk the flour, cinnamon, ginger, allspice, baking powder, baking soda, nutmeg, cloves and salt in a medium bowl.
Whisk the egg yolks, melted butter and molasses in a large bowl. Beat the egg whites and granulated sugar with a mixer on medium-high speed until stiff peaks form, 5 minutes. Stir the
flour mixture into the yolk mixture until smooth. Stir one-third of the whites into the batter with a rubber spatula, then fold in the remaining whites in two batches. Spread the batter in the prepared pan; bake until a toothpick inserted into the center comes out with just a few crumbs, 10 to 12 minutes.
Immediately sift confectioners' sugar generously over the top of the warm cake and loosen the edges with a knife; lay a clean kitchen towel (not terry cloth) over the cake. Place another baking sheet over the towel and flip the cake with the baking sheets to invert it onto the towel. Remove the top baking sheet and parchment. Starting at a short end, roll up the cake and the towel together into a spiral. Transfer seam-side down to a rack and let cool completely.
Meanwhile, make the filling: Beat the heavy cream and 3/4 cup confectioners' sugar with a mixer on high speed until soft peaks form. Beat in the mascarpone and vanilla. (Do not overbeat.) Fold in the chocolate chips and candied citrus with a rubber spatula.
Make the topping: Combine the remaining 2 tablespoons confectioners' sugar, the cinnamon, ginger, allspice, nutmeg and cloves in a bowl. Gently unroll the cake. Spread the filling over the cake about 1/4 inch from the edges; reroll (without the towel). Trim the ends with a serrated knife. Transfer to a platter; dust with the spice mixture.