Double Espresso Roll Cake

Coffee flavored cake called Mocha cake is a favorite in the Philippines. It is sold at bakeshops as a round layer, sheet, or Swiss roll cakes and often served at birthday parties. These are chiffon, very soft, and spongy cakes unlike American-style jelly roll cakes. I love this not too sweet Filipino version that I adapted from this recipe, and for intense coffee flavor I used freshly brewed coffee plus espresso powder.

Double Espresso Roll Cake
1 cup sifted flour
½ teaspoon salt
½ cup sugar
½ tablespoon baking powder
1 tablespoon espresso powder
¼ cup light olive or grapeseed oil
6 tablespoons hot brewed espresso coffee
4 egg yolks
4 egg whites
¼ teaspoon cream of tartar
¼ cup sugar

• Preheat oven to 350°F. Line a jelly roll pan with parchment paper.
• In a bowl of standing mixer, combine flour, salt, ½ cup sugar, baking powder, and espresso powder. Make a well in the center and pour in oil and hot coffee. With the paddle attachment, beat mixture on medium low for 3 minutes. Continue mixing, adding egg yolks one at a time, blending well after each addition, until thoroughly mixed. Transfer into another bowl and set aside.
• Wash the bowl very well and wipe dry, or use another bowl. Put in the egg whites and cream of tartar. Beat with wire whisk attachment at medium speed until frothy. Gradually add the ¼ cup sugar, beating until mixture is stiff and glossy. 
• With rubber spatula, gently fold one fourth of beaten egg whites into batter, scraping bottom of bowl, until lightly blended. Gently fold the batter into the rest of the beaten egg white. Pour evenly into the prepared pan and smooth top with an offset spatula. Bake for 20 to 25 minutes. 
• Turn the cake out on a towel lightly sprinkled with powdered sugar. Peel off the parchment paper. Starting from the narrow side, roll the still warm cake with the towel and leave on a wire rack to cool completely. Unroll the cake and transfer onto a parchment paper. Spread with a thin layer of Espresso Buttercream Frosting and reroll the cake, frost the outside of the roll. Refrigerate for at least 2 hours before slicing. Keep leftover slices in the refrigerator or freezer.

Espresso Buttercream Frosting
2 large egg whites, at room temperature
1/8 teaspoon salt
½ cup brewed espresso coffee
11 tablespoons plus 1 tablespoon sugar
12 tablespoons butter, cut into 1 tablespoon pieces and softened
1 tablespoon espresso powder

• Put egg whites and salt in the bowl of a standing mixer with the wire whisk attachment.
• Stir together brewed coffee and 11 tablespoons sugar in a  heavy saucepan until sugar is dissolved, then bring to a boil over moderate heat, without stirring, brushing any sugar crystals down side of pan with a pastry brush dipped in water.
• When syrup reaches a boil, start beating egg whites at medium-high speed until frothy, then gradually add remaining tablespoon sugar and espresso powder and beat at medium speed until whites just hold soft peaks. Do not beat again until sugar syrup is ready.
• Meanwhile, attach candy thermometer on the saucepan and continue boiling until syrup registers 238°F. Immediately remove from heat and with mixer at high speed, slowly pour hot syrup in a thin stream down side of bowl into whites, beating constantly. Beat, scraping down side of bowl with a rubber spatula, until meringue is cool to the touch, about 10 minutes. It is important that meringue is properly cooled before proceeding. With mixer at medium speed, gradually add butter 1 piece at a time, beating well after each addition until incorporated. Continue beating until buttercream is smooth. Mixture may look curdled before all of the butter is added but will come back together by the time beating is finished.