6 large eggs, separated
1/4 tsp. cream of tartar
3/4 cup sugar, divided
1/3 cup plus 1 Tbsp. dutch processed cocoa
1 1/2 cups whipping cream
2 Tbsp. icing sugar
1/2 packet whipping cream stabilizer
1/2 tsp. vanilla
1 Tbsp. liqueur
1/2 cup whipping cream
6 oz. bittersweet chocolate, chopped
1 Tbsp. liqueur
Lightly grease a 10 1/2" by 15 1/2" jelly roll pan. Line sides and bottom with wax paper by cutting a 12" by 16" piece of paper, cut a diagonal slash in each corner, folding ends to form corners. Lightly butter and flour paper.
In a large, clean bowl, beat egg whites with cream of tartar on medium-high speed until soft peaks form.
Gradually add 1/4 cup sugar and continue beating until stiff peaks form.
In another large bowl, beat egg yolks, 1/3 cup cocoa and 1/2 cup sugar until thick, about 3 minutes.
Stir about 1/4 of egg whites into yolk mixture. Fold in remaining whites.
Spread mixture into prepared pan. Bake at 350 degrees F for 12 to 15 minutes.
Cool completely in pan on cooling rack. Sift with remaining cocoa.
In a medium bowl, beat all filling ingredients on medium-high speed until stiff.
Turn cake layer out onto a sheet of foil. Peel off wax paper.
Spread cake evenly with cream, leaving a 1" border around edges.
Roll tightly starting at a long side, using foil as an aid.
In a small saucepan, heat cream until boiling.
Remove from heat and add chocolate and liqueur. Let stand 5 minutes, then whisk until smooth.
Transfer to a bowl and place in refrigerator until chilled and thick, stirring occasionally.
Whisk until soft peaks form. Immediately spread over top and sides of roll. Using the tines of a fork, make wavy lines on the ganache to look like bark.
Makes 8 to 12 servings