Preheat oven to 350 degrees F (180 degrees C) and place the oven rack in the
center of the oven. Butter, or spray with a non stick vegetable spray, a 17 x 12
inch (43x30 cm) baking pan. Line the pan with parchment paper and then butter
and flour the parchment paper.
While the eggs are still cold,
separate the eggs, placing the whites in one bowl and the yolks in another. Cover and bring to room temperature before using
30 minutes). Meanwhile melt the chocolate in a
heatproof bowl placed over a saucepan of simmering water. Remove from heat and
In the bowl of your electric mixer
(or with a hand mixer) place the
egg yolks and 1/4 cup of sugar and beat until light
and fluffy (about five minutes). (When you slowly raise the beaters, the
batter will fall back into the bowl in a slow ribbon.) Beat in the vanilla
extract. Scrape down sides of bowl. Add the melted chocolate and
beat only to combine.
In a clean mixing bowl, with the
whisk attachment, beat the egg whites until foamy. Add the cream of tartar
and beat at medium-high speed until soft peaks form. Gradually beat in the
remaining 2 tablespoons sugar until stiff peaks form.
fold a small amount of the egg
whites into the egg yolk mixture using a rubber spatula or whisk. Fold in the remaining whites just until incorporated. Don't over mix or
the batter will deflate. Spread the batter evenly into the prepared pan. Bake until the cake is puffed, has lost its shine, and
springs back when gently pressed, about 15 - 17 minutes. Remove from oven and
place on wire rack to cool. Cover the cake with a clean, slightly damp towel.
Chocolate Whipped Cream: In a large mixing bowl place the whipping cream,
vanilla extract, sugar, and
cocoa powder and stir to combine. Cover with plastic wrap and place the bowl and
wire whisk in the refrigerator for one hour. Then beat the mixture until stiff peaks form. Once the cake has cooled,
spread with the cream (set 2 tablespoons aside) and then
gently roll the cake, peeling off the parchment paper as you roll (the cake may
crack). Trim one end of the cake at an angle and set it aside. Then place the
cake, seam side down, on your serving platter. Take the slice of
reserved cake and, using the reserved whipped cream, attach it to the side of
the cake. Cover and chill until serving time. Just before serving remove cake
from fridge, dust with confectioners sugar and decorate with mushrooms.