Black Forest Cake Roll
Black Forest Cake (Forêt Noire) is a German dessert Schwarzwälder Kirschtorte. It combines rich chocolate cake layers with cherries and Chantilly. This recipe is inspired by chef Thierry Bamas (MOF). The technique used for the chocolate sponge isn't something we are familiar with. It is based on a pate a choux-like-dough concept which offers an unique flexibility. The whole thing is then layered with dark cherry marmalade and luscious vanilla Chantilly and glazed with chocolate ganache. Make a day ahead.
Yields one half size sheet pan 18X13 inch (46X33 cm) and one 9X13 inch (23X33 cm. Or, one large 16X22 inch/40.6X55.9 cm sheet pan.
Grease tray and silicone mat or parchment with cooking spray or oil.
Sift flour and cocoa powdered together. Mix eggs and egg yolks with an immersion blender; set aside.
For the meringue: In the stand mixer fitted with the whisk attachment, beat egg whites and cream of tartar and one-third of the sugar on medium speed; let it run. Meanwhile, and just like a pate a choux, gather in a saucepan, milk, butter and salt. Remove from the heat and transfer mixture to a large pastry bowl. Add the sifted powder and mix to combine with the whisk and incorporate eggs.
Increase mixer speed to high and beat egg whites until stiff peaks form, adding remaining sugar gradually.
Turn oven on to 450ºF/230ºC (set it to 400ºF/205ºC if using a fan oven). Fold one-third of the meringue into the chocolate mixture and add the remaining. Scale out 350g of batter for the half size baking tray and use the remaining for the 1/4 size pan. Spread into even sheet.
Bake for 7 minutes. Let cool completely and freeze until ready to use.
Soak gelatin in cold water to soften, and drain. Bring the first part of heavy cream (300g) to a boil along with vanilla. Add white chocolate and mix using an immersion blender. Add gelatin and mix. Add the chilled heavy cream and mix. Refrigerate mixture overnight.
In a food processor, blend all ingredients together. Roll out pastry into a 0.16 inch/4 mm thick sheet and freeze. Cut into very small cubes and freeze. Spread onto a baking tray lined with silicone mat or parchment. Bake at 350ºF/180ºC for about 20 minutes (keep an eye on it) – let cool. There will be plenty of leftover crumble... save it for you morning granola!
Crunchy praliné is going to be the base of the cake. Microwave cocoa butter; set aside. Meanwhile, melt chocolate to 113ºF/45ºC and stir in melted cocoa butter. Add praliné and feuilletine (feuilletine, or pailleté, is a crispy confection made from thin, sweetened crêpes. It can b subbed for crushed corn flakes). Then add the crumble – mix to combine and roll out into a 0.23 inch/6 mm thick rectangle between a silicone mat and parchment paper and refrigerate or freeze. Once set, carefully cut into two equal part that should match the cake dimensions... 11X3 inch 28X7.5 cm, and freeze. Crunchy praliné scraps can be reused; rewarm first.
Melt out frozen cherries along with the glucose. Meanwhile, mix sugar and pectin together. When cherries are soft enough, mix using an immersion blender. Heat up and stir in the sugar-pectin mixture. Bring to a boil and cook for 2 minutes. Add cherry liquor if desired – bring to a quick boil and set aside.
Top frozen chocolate biscuit with parchment and flip onto the countertop and remove silicone mat. Warm up cherry marmalade and spread it (300g) evenly onto the biscuit and freeze for 15 min. Meanwhile, whip two-third of the Chantilly to medium-firm peaks (save remaining for the final decoration). Cover the biscuit with 300g vanilla Chantilly. Make a quarter turn clockwise and roll into a log starting from noon to 6 o'clock. Use the parchment paper and a rectangle device, and gently tight it up. If some of the filling comes out, fix it with a spatula. Freeze cake for a couple of hours and re-tight again. Freeze cake for 4 hours at least prior to glaze.
Melt chocolate; partially. Meanwhile, bring to a boil heavy cream along with honey and glucose. Mix in chocolate gradually. When ganache temperature reaches 113ºF/45ºC, add butter and mix using an immersion blender. Use at 90/95ºF (32/35ºC). Ganache can be stored in the refrigerator. Before using, rewarm slowly over a bain-marie stirring ever so often. Do not over heat.
Place a cooling rack onto a large baking tray lined with plastic wrap. Place log onto rack and glaze. Transfer to a flat surface, sprinkle some cocoa nibs or chocolate pearls and trim off ends. The log should measure 11 inch/28 cm. Carefully transfer cake onto the crunchy praliné base. Do likewise with the other cake if so. Whip remaining Chantilly and pipe out large dollops using a large plain pipping tip. Create holes using a melon baller (warm up in hot water prior to dig into the filling). Fill holes with remaining cherry marmalade. Cherries in brandy (cerises champagne) can be used for the last touch up. Refrigerate cake for a few hours to thaw before serving.
Black forest cake can be made in advance and kept frozen for a up to a month. Once thawed, keep refrigerated for up to 3 days.