1. Heat oven to 375 degree F. Coat 15 x 10 x 1-inch jelly-roll pan with nonstick cooking spray. Line with waxed paper; coat paper with spray. Dust a clean kitchen cloth with 2 tablespoons of confectioners sugar.
2. In a small bowl, whisk flour, baking powder and salt. In medium-size bowl, with electric mixer on medium speed, beat eggs for about 5 minutes until thick and lemon colored, gradually adding granulated sugar until well blended. Beat in vanilla. In 2 additions, fold in flour mixture until combined. Scrape batter into prepared pan, spreading evenly.
3. Bake at 375 degree F for 10 minutes until lightly golden and center springs back when lightly pressed. Cool in pan on rack for 5 minutes. Then, invert cake onto sugar-dusted cloth. Remove pan and waxed paper. Dust top of cake with another 2 tablespoons confectioners sugar. Beginning at a short end, roll up cake, enclosing towel (photo 1). Place cake, seam side down, on a cooling rack. Cool completely.Filling:
4. In a small bowl, stir together mascarpone and confectioners sugar. Unroll cake and spread with sweetened mascarpone. Top with raspberry jam, leaving a 1/4-inch border on the short ends. Beginning at a short end of cake, arrange rows of raspberries on cake (photo 2).
5. Carefully roll up cake without towel (photo 3). Cover with plastic wrap and refrigerate 1 hour. Dust with confectioners sugar before serving.