Strawberry Roulade

This roll cake turns a classic roulade inside out by putting the strawberries from the filling into the batter for the sponge cake. The result is a beautiful rosy pink cake with a velvety vanilla buttercream filling. Don’t let the Italian buttercream method intimidate you, it’s much simpler than it sounds and the result is more than worth the effort.

Strawberry Roulade was the technical bake for Cake Week of Season 3 of The Great Canadian Baking Show.

Ingredients

Cake:

• 1 ½ cups chopped strawberries
• ¾ cup granulated sugar, divided
• 1 cup cake flour, sifted
• 1 ½ tsp baking powder
• ½ tsp salt
• 3 eggs, separated, at room temperature
• ¼ cup vegetable oil
• 1 tsp vanilla
• Pink gel food colouring
• ¼ tsp cream of tartar
• ¼ cup icing sugar
• Whole strawberries for decorating

Italian Meringue Buttercream:

• ⅔ cup granulated sugar
• 3 tbsp water
• 2 egg whites
• ⅛ tsp cream of tartar
• ½ tsp fine salt
• 1 cup butter, softened
• 2 tsp vanilla bean paste

Preparation

Heat oven to 375F degrees. 

Spray a rimmed baking sheet (17x12-inch) with cooking spray and line with parchment paper to overhang on the two long sides. Set aside. 

Add strawberries and ¼ cup sugar into the bowl of a food processor. Blitz until well combined. Set the puree aside.

In a large bowl, whisk together flour, ¼ cup sugar, baking powder and salt. Set aside. 

In a medium bowl, whisk together the egg yolks, strawberry puree, oil and vanilla. Add to the flour mixture and stir until just combined. Using a toothpick, add a small amount of the gel food colouring to achieve a delicate pink colour. (Keep in mind that the addition of egg whites in the next steps will lighten the mixture slightly).

In another large bowl, whip the egg whites with a hand mixer on high until foamy. Add cream of tartar and continue to whip until they hold soft peaks. Add the remaining ¼ cup sugar one tablespoon at a time until the egg whites hold stiff peaks. 

Stir ¼ of the egg whites into the batter until combined and no white streaks remain. Gently fold the remaining egg whites into batter until no streaks remain. Spread batter evenly into prepared pan and bake until the cake springs back when lightly touched, about 23 minutes. Cool 2 minutes.  

Loosen the edges of the cake from the pan using a paring knife. Turn the cake out onto a cooling rack and remove the parchment paper. Transfer the cake, parchment-side up, to a clean tea towel. Starting at the short edge, gently roll the cake up into the towel. Place the roll onto a cooling rack, seam side down and set aside to cool completely. 

Buttercream: 

In a small saucepan, combine the sugar and water. Bring to a boil over medium-high heat. Reduce heat to medium and cook until mixture reaches 238F/120C degrees, brushing the sides of the pan with a damp pastry brush if sugar appears on sides of pan (this prevents crystallization). Remove from heat and let stand just long enough to allow bubbling to subside. 

Meanwhile, get the egg whites ready.

Place the egg whites in the bowl of a stand mixer fitted with a whisk attachment. Whisk on medium-high until foamy. Add cream of tartar and continue to whisk until soft peaks form. *Note, if the egg whites are ready before the sugar has reached temperature, keep the mixer moving very slowly on low until sugar is ready.

Gradually stream the sugar syrup along the side of the mixing bowl into the egg whites with the mixer running on medium. Turn the mixer up to medium-high and continue to beat until glossy, stiff and cooled to room temperature, about 4 to 6 minutes. Add salt. 

With the mixer running on high, add butter one tablespoon at a time, whisking between additions to incorporate until smooth and fluffy. This will take 5 to 7 minutes. Add vanilla bean paste and continue to whisk for 1 minute. 

Unroll the cake and spread the buttercream evenly to the edges. Roll the cake back up, trim the ends and place seam side down on a serving platter. Decorate as desired with fresh strawberries.

Yield: Makes 1 roll