Step 1

Place egg whites in a bowl. Preheat oven to 325°. Line bottom of a greased 15x10x1-in. baking pan with parchment; grease paper. Sift cocoa, flour and salt together twice.

Step 2

In a large bowl, beat egg yolks until slightly thickened. Gradually add 1/3 cup confectioners' sugar, beating on high speed until thick and lemon-colored. Beat in vanilla. Fold in cocoa mixture (batter will be very thick).

Step 3

Add cream of tartar to egg whites; with clean beaters, beat on medium until soft peaks form. Gradually add remaining confectioners' sugar, 1 tablespoon at a time, beating on high after each addition until sugar is dissolved. Continue beating until soft glossy peaks form. Fold a fourth of the whites into batter, then fold in remaining whites. Transfer to prepared pan, spreading evenly.

Step 4

Bake until top springs back when lightly touched, 9-11 minutes. Cover cake with waxed paper; cool completely on a wire rack.

Step 5

Remove waxed paper; invert cake onto an 18-in.-long sheet of waxed paper dusted with confectioners' sugar. Gently peel off parchment.

Step 6

In a small bowl, beat cheeses and sugar until blended. Stir in Kahlua, orange zest and vanilla. Spread over cake to within 1/2 in. of edges. Roll up jelly-roll style, starting with a short side. Trim ends; place on a platter, seam side down.

Step 7

Refrigerate, covered, at least 1 hour before serving. To serve, dust with confectioners’ sugar.