Preheat oven to 350°F. Line a 17×12 inch jelly roll sheet pan with parchment paper. Make sure the parchment paper sticks up at least an inch above the sides of the pan on all sides. You’ll use the parchment paper later to lift the cake out of the pan and roll it up.
Whisk the flour, cocoa, baking powder and salt together in a medium bowl and set aside.
In a large bowl, combine the egg yolks and sugar and whisk together until well combined.
Add the sour cream, melted butter and vanilla extract and whisk together until well combined.
Add the dry ingredients and gently whisk together until well combined, then set aside.
Add the egg whites to a large mixer bowl and whip of high speed until stiff peaks form.
Gently fold about 1/3 of the whipped egg whites into the chocolate mixture to loosen up the batter.
Add the remaining egg whites and gently fold together until well combined.
Spread the cake batter evenly into the prepared pan and bake for 10-12 minutes, or until the top of the cake springs back when toughed and a toothpick inserted comes out clean.
Remove the cake from the oven and immediately lift the cake out of the pan using the parchment paper and place it on the counter.
While the cake is hot, use the parchment paper the cake was baked in and start at the shorter end of the cake to slowly roll the cake up. Set the cake aside to cool completely.
When the cake has cooled and is ready to be filled, make the filling. Add the heavy whipping cream, powdered sugar, vanilla extract and salt to a large mixer bowl and whip on high speed until soft peaks form.
Add the mascarpone cheese to the whipped cream and whip until stiff peaks form. It will happen fairly quickly.
Unroll the cake roll very carefully, looking out for areas where it may be sticking to release it. You can use an offset spatula or something similar and run it along the parchment paper as you unroll the cake to help release it as it unrolls.
Spread the filling evenly onto the unrolled cake, then roll it back up without the parchment paper.
Wrap it up in plastic wrap with the seam side down and refrigerate for at least an hour to firm up.
When you’re read to decorate the cake, make the chocolate ganache. Add the chocolate to a medium sized bowl and set aside. Heat the cream in the microwave just until it begins to boil, then pour it over the chocolate.
Allow the chocolate and cream to sit for a few minutes, then whisk until smooth. Let the ganache cool to about room temperature, then transfer to a large mixer bowl.
Whip on high speed until lightened in color and thick enough to spread.
To decorate the cake, use a large serrated knife to gently cut off a piece of the log about 3 inches in length. Make the cut with a slight diagonal.
Use some of the chocolate ganache to attache the small log to the side of the larger log.
Spread the remaining chocolate ganache all over the cake, then use a fork to create bark-like lines all over it. Decorate with sugared cranberries and rosemary (instructions in notes), if desired.
Refrigerate the cake until ready to serve.
Preheat the oven to 225 degrees F (110 degrees C). Line 2 cookie sheets with parchment paper or aluminum foil.
In a large glass or metal bowl, use an electric mixer to whip egg whites until foamy. Add cream of tartar, salt, and vanilla. Continue whipping until the whites hold soft peaks. Gradually sprinkle in the sugar so that it does not sink to the bottom, and continue whipping until the mixture holds stiff shiny peaks.
Place a round tip into a pastry bag, and fill the bag half way with the meringue. To pipe the mushroom caps, squeeze out round mounds of meringue onto one of the prepared cookie sheets. Pull the bag off to the side to avoid making peaks on the top. For the stems, press out a tiny bit of meringue onto the other sheet, then pull the bag straight up. They should resemble candy kisses. Do not worry about making all of the pieces exactly the same. The mushrooms will look more natural if the pieces are different sizes. Dust the mushroom caps lightly with cocoa using a small sifter or strainer.
Bake for 1 hour in the preheated oven, or until the caps are dry enough to easily remove from the cookie sheets. Set aside to cool completely. Melt the coating chocolate in a metal bowl over simmering water, or in a glass bowl in the microwave, stirring occasionally until smooth.
Poke a small hole in the bottom of a mushroom cap. Spread chocolate over the bottom of the cap. Dip the tip of a stem in chocolate, and press lightly into the hole. When the chocolate sets, they will hold together. Repeat with remaining pieces. Store at room temperature in a dry place or tin.
Ingredients
Directions
Preheat oven to 350°F. Line a 17×12 inch jelly roll sheet pan with parchment paper. Make sure the parchment paper sticks up at least an inch above the sides of the pan on all sides. You’ll use the parchment paper later to lift the cake out of the pan and roll it up.
Whisk the flour, cocoa, baking powder and salt together in a medium bowl and set aside.
In a large bowl, combine the egg yolks and sugar and whisk together until well combined.
Add the sour cream, melted butter and vanilla extract and whisk together until well combined.
Add the dry ingredients and gently whisk together until well combined, then set aside.
Add the egg whites to a large mixer bowl and whip of high speed until stiff peaks form.
Gently fold about 1/3 of the whipped egg whites into the chocolate mixture to loosen up the batter.
Add the remaining egg whites and gently fold together until well combined.
Spread the cake batter evenly into the prepared pan and bake for 10-12 minutes, or until the top of the cake springs back when toughed and a toothpick inserted comes out clean.
Remove the cake from the oven and immediately lift the cake out of the pan using the parchment paper and place it on the counter.
While the cake is hot, use the parchment paper the cake was baked in and start at the shorter end of the cake to slowly roll the cake up. Set the cake aside to cool completely.
When the cake has cooled and is ready to be filled, make the filling. Add the heavy whipping cream, powdered sugar, vanilla extract and salt to a large mixer bowl and whip on high speed until soft peaks form.
Add the mascarpone cheese to the whipped cream and whip until stiff peaks form. It will happen fairly quickly.
Unroll the cake roll very carefully, looking out for areas where it may be sticking to release it. You can use an offset spatula or something similar and run it along the parchment paper as you unroll the cake to help release it as it unrolls.
Spread the filling evenly onto the unrolled cake, then roll it back up without the parchment paper.
Wrap it up in plastic wrap with the seam side down and refrigerate for at least an hour to firm up.
When you’re read to decorate the cake, make the chocolate ganache. Add the chocolate to a medium sized bowl and set aside. Heat the cream in the microwave just until it begins to boil, then pour it over the chocolate.
Allow the chocolate and cream to sit for a few minutes, then whisk until smooth. Let the ganache cool to about room temperature, then transfer to a large mixer bowl.
Whip on high speed until lightened in color and thick enough to spread.
To decorate the cake, use a large serrated knife to gently cut off a piece of the log about 3 inches in length. Make the cut with a slight diagonal.
Use some of the chocolate ganache to attache the small log to the side of the larger log.
Spread the remaining chocolate ganache all over the cake, then use a fork to create bark-like lines all over it. Decorate with sugared cranberries and rosemary (instructions in notes), if desired.
Refrigerate the cake until ready to serve.
Preheat the oven to 225 degrees F (110 degrees C). Line 2 cookie sheets with parchment paper or aluminum foil.
In a large glass or metal bowl, use an electric mixer to whip egg whites until foamy. Add cream of tartar, salt, and vanilla. Continue whipping until the whites hold soft peaks. Gradually sprinkle in the sugar so that it does not sink to the bottom, and continue whipping until the mixture holds stiff shiny peaks.
Place a round tip into a pastry bag, and fill the bag half way with the meringue. To pipe the mushroom caps, squeeze out round mounds of meringue onto one of the prepared cookie sheets. Pull the bag off to the side to avoid making peaks on the top. For the stems, press out a tiny bit of meringue onto the other sheet, then pull the bag straight up. They should resemble candy kisses. Do not worry about making all of the pieces exactly the same. The mushrooms will look more natural if the pieces are different sizes. Dust the mushroom caps lightly with cocoa using a small sifter or strainer.
Bake for 1 hour in the preheated oven, or until the caps are dry enough to easily remove from the cookie sheets. Set aside to cool completely. Melt the coating chocolate in a metal bowl over simmering water, or in a glass bowl in the microwave, stirring occasionally until smooth.
Poke a small hole in the bottom of a mushroom cap. Spread chocolate over the bottom of the cap. Dip the tip of a stem in chocolate, and press lightly into the hole. When the chocolate sets, they will hold together. Repeat with remaining pieces. Store at room temperature in a dry place or tin.