Chocolate Swiss Roll Cake

To make the ultimate chocolate swiss roll, fill this chocolate sponge cake with whipped cream and cover it with a thin layer of ganache. All of your childhood fantasies have undoubtedly come true.

Ingredients :

For the chocolate sponge cake

• 3/4 cup (100g) cake flour

• 1/2 cup (56g) cocoa powder

• 3 1/2 tablespoons (26g) cornstarch

• 3/4 cups (170g) granulated sugar

• 6 large eggs, room temperature

• 1/2 teaspoon (3g) kosher salt

• 4 tablespoons (58g) melted unsalted butter

• 1 teaspoon vanilla extract

• 2 tablespoons cocoa powder

For the stabilized whipped cream

• 1 1/2 tablespoons cold water

• 1 teaspoon plain gelatin powder

• 1 1/2 cups heavy cream

• 1/2 cup (50g) powdered sugar

• 1 teaspoon vanilla extract

For the chocolate ganache

• 1 cup (170g) semi-sweet chocolate chips

• 1/2 cup heavy cream

• 1 teaspoon vanilla extract, optional

STEPS :

     1. Sift the dry ingredients :

Sift the cake flour, cocoa powder, and cornstarch three times into a large mixing bowl. Set aside the dry ingredients.

     2. Warm sugar in the oven while it preheats :

Line a half-sheet pan with parchment paper, then sprinkle the sugar evenly over the paper.

Preheat the oven to 350°F. Preheat the oven to 400 degrees Fahrenheit. At step 4, you'll place the sugar in the oven while it preheats and remove it when it's warm to the touch.

     3. With a stand mixer, whisk the eggs as follows :

While the sugar is warming, lightly beat the eggs in a stand mixer fitted with the whisk attachment on low speed for 30 to 45 seconds, or until they look frothy with little bubbles.

     4. Eggs with sugar added :

The sugar should be warm to the touch by now. The warm sugar and salt should be added to the eggs as the mixer is still running after removing the pan from the oven and holding the parchment paper by the sides.

Increase the mixer speed to medium-high once all of the sugar has been added to the eggs. Beat the mixture for 8 minutes, or until it is lemon-yellow and very thick.

     5. Prepare the sheet pan :

Spray the chilled half-sheet jelly roll pan gently with baking spray while the eggs are beating (be sure to not spray the sides). Line the sheet pan with the parchment paper that was used to hold the sugar (or a new one).

     6. Sift in the dry ingredients and add the butter and vanilla :

Remove the bowl from the stand mixer once the eggs have completed whipping and sift the dry ingredients into the mixer bowl with the eggs.

Fold the flour into the eggs gradually using a large rubber spatula. In order to incorporate the flour into the eggs, scrape the sides of the bowl first, then move in toward the center. The egg mixture should be lifted over the flour. Continue gradually, being careful not to deflate the eggs too much, until no flour streaks remain.

When most of the flour has been incorporated, add the melted butter and vanilla extract. After folding in the flour and butter, the mixture will go from voluminous to deflated, but it will still look thick and shiny.

     7. Pour batter into prepared sheet and bake :

Spoon the batter onto the prepared baking sheet. Spread and level the batter in the pan with an offset spatula. Expel any huge bubbles by gently tapping the pan against the countertop three or four times. For 10 to 12 minutes, bake the cake. When you gently press on the center of the cake, it will have doubled in size and will feel spongy.

     8. Sift cocoa powder over a tea towel :

Sift the cocoa powder over a clean tea towel to lightly dust it.

     9. Flip cake out onto tea towel :

Remove the pan from the oven once the cake has done baking. Remove the cake from the pan with a knife and immediately flip it onto the cocoa-dusted towel. When you flip the cake out, less cocoa will spray everywhere if the pan is kept in a low position.

     10. Roll the cake and cool on rack :

While the cake is still hot, roll it into a tube form, beginning with the long edge. There is no requirement to remove the parchment paper. Let the cake to cool for 45 minutes in this shape on a cooling rack.

     11. Combine water and gelatin to make stabilized whipped cream :

Prepare the stabilized whipped cream near the conclusion of the chilling time. Combine the cold water and powdered gelatin in a 1-cup microwave-safe bowl.

Microwave the mixture for 15-20 seconds on high power. Remove the mixture from the microwave when it begins to bubble and let it to cool but not firm up. The gelatin will have dissolved and the mixture will be sloppy.

     12. Whip the heavy cream :

In a mixing basin, combine the heavy cream. Make use of an electric hand mixer with the whisk attachment. Set it to medium speed for 2 minutes, or until the beater leaves ribbons of cream behind.

     13. Add in the gelatin, powdered sugar, and vanilla :

Lower the mixer speed to low and carefully trickle in the gelatin. When all of the gelatin has been added, combine it with the powdered sugar and vanilla extract. Stop the mixer, then scrape the bowl's sides.

     14. Finish the whipped cream :

Continue mixing again, this time on medium-high for 3 to 4 minutes, or until the whipped cream holds stiff peaks and stands straight up when the beaters are removed.

If the cake is still warm to the touch, place the cream in a closed container in the refrigerator until ready to fill the cake.

     15. Unroll the cake :

When the cake has completely cooled and is no longer warm to the touch, carefully unroll it and peel away the parchment paper.

     16. Spread whipped cream on cake and reroll the cake :

Give the cake a layer of whipped cream between 1/8 and 1/4 inch thick, leaving a 1-inch border on one of the short ends. Begin rolling the cake back into a tube from the cream-covered short end. Roll the tube tightly toward the other end using the towel.

     17. Wrap cake in plastic wrap and refrigerate :

Cover the tube tightly in plastic wrap. Twist the wrapping ends together to form a tight cylindrical shape. Let the chocolate swiss roll to set in the refrigerator for at least 2 hours.

     18. Prepare the chocolate ganache :

Prepare the chocolate ganache an hour before serving the Swiss roll. To make the ganache, fill a 1-quart microwave-safe bowl halfway with heavy cream. Microwave for 1 minute 30 seconds, or until it starts to steam. You may also make this in a stovetop pot. You only want it to warm up, not boil.

Add the chocolate chips and vanilla extract to the bowl and shimmy it slightly so that the cream covers all of the chips. Let the chocolate to soak for 3 to 4 minutes in the cream.

Mix together the cream and chocolate until smooth. If any chunks remain, microwave the ganache for 20 seconds before whisking again. Let the ganache to cool for 12 to 15 minutes at room temperature before serving.

     19. Unwrap and glaze the chocolate swiss roll :

Take the swiss roll from the refrigerator and discard the plastic wrap. Put the roll on a cooling rack placed on top of a sheet pan.

Pour the ganache over the top of the roll and cover it evenly using an offset spatula or the back of a spoon. To use up all of the ganache, scoop up the excess from the pan bottom and repeat the pouring instructions if you wish to double the ganache.

Move the cake to a tray and chill for 20 minutes, or until the ganache is slightly sticky to the touch.

     20. Serve :

Cut into slices and serve. Refrigerate leftovers covered and consume within 2 days.