Line a greased 15-in. x 10-in. x 1-in. baking pan with parchment paper; grease the paper and set aside.
In a large bowl, beat eggs for 3 minutes. Gradually add sugar, beating for 2 minutes or until mixture becomes thick and lemon-colored. Stir in water and vanilla. Combine the flour, baking powder and salt; add to egg mixture and beat until smooth.
Spread batter evenly into prepared pan. Bake at 350° for 12-15 minutes or until cake springs back when lightly touched. Cool for 5 minutes.
Invert cake onto a kitchen towel dusted with confectioners' sugar. Gently peel off parchment paper. Roll up cake in the towel jelly-roll style, starting with a short side. Cool completely on a wire rack.
Unroll cake; spread ice cream evenly over cake to within 1/2 in. of edges. Roll up again. Place seam side down on a serving platter. Cover and freeze for at least 1 hour.
Melt four squares of chocolate; spread over a parchment paper-lined baking sheet. Refrigerate for 30 minutes.
Break chilled chocolate into 3-in. x 1-in. pieces. Melt remaining chocolate; spread over top, sides and ends of cake. Working quickly, place chocolate pieces on cake to resemble bark. Freeze until serving. Remove from the freezer 10 minutes before cutting. Yield: 10 servings.