Preheat oven to 375°F. Lightly grease a 15-by-10-inch jelly-roll pan. Line pan with parchment paper and grease paper.
Make cake: Whisk together flour, cinnamon, ginger and 1/4 tsp. salt.
With electric mixer on high, beat egg yolks, granulated sugar and brown sugar until thick and pale, about 3 minutes. On low, mix in pumpkin and then dry ingredients.
With a clean bowl and beaters, beat egg whites and remaining 1/4 tsp. salt until stiff but not dry. Fold into batter in 3 additions. Scrape into pan; spread evenly. Bake until springy to touch, about 15 minutes.
Dust a clean kitchen towel with confectioners' sugar. Loosen cake from pan; turn out onto towel and peel off parchment. Roll cake lengthwise in towel; turn seam to bottom and let cake cool.
Make filling: Beat all 5 ingredients on high until smooth, about 3 minutes. Unroll cake, spread filling evenly and reroll. Trim ends diagonally and dust with confectioners' sugar.
