When we think of peanut butter, we usually think of jelly or of chocolate. But espresso? They say, coffee brings out the chocolate flavour in cakes, but it also perfectly complements peanut butter!
So I flavoured the chocolate sponge cake with espresso powder. The powder mixes easily into the batter and doesn’t have to be dissolved in water, which is why I prefer it to instant coffee in baking. If you are not a coffee lover, just leave the espresso powder out.
At first, I wanted to make my favourite chocolate layer cake recipe with the peanut butter filling, but then I thought it would be better to combine the filling with a lighter cake. Although the filling is airy and mousse-like, it is still rich, made with cream cheese, whipped cream and peanut butter. The only fat in the sponge cake are the eggs.
You can make this recipe as a Swiss roll, or cut the baked sponge cake into 3 even rectangles to have a rectangular layer cake; you can also bake it in 2 9″ round pans and make it into a round layer cake.
I have covered the cake with an espresso-flavoured chocolate ganache glaze – but you could just dust it with some icing sugar for a simple finish.
Espresso-flavoured chocolate sponge cake
2/3 cup sugar
1/2 cup flour
1/3 cup cornstarch
1/2 cup cocoa
pinch of salt
1 tbsp vanilla sugar (or 1 tsp vanilla extract)
3 tbsp espresso powder
Preheat the oven to 425 degrees. Prepare a jelly roll pan by lining it with parchment paper.
Beat the eggs with the salt and sugars in an electric stand mixer with the whisk attachment until tripled in volume and light in colour.
Sift together the flour, cornstarch, cocoa, and espresso powder and gently fold into the egg mixture without deflating it.
Pour the batter into the prepared pan and bake for about 10 minutes. The cake is done as soon as the top feels dry. Don’t over-bake it or you will have a very dry cake that will crack when rolling it up.
While the cake is baking, sprinkle a damp tea towel with 2-3 tbsp sugar. As soon as the cake is finished, invert it onto the prepared tea towel, peel off the parchment paper, and roll up the cake from the short side with the towel inside. This prevents the sponge from drying out and lets you roll it up later. Let cool on the counter while you prepare the filling.
Peanut butter mousse filling
4 oz. peanut butter
4 oz. cream cheese
1/2 cup icing sugar
1 tbsp vanilla sugar
1/2 cup whipping cream
Beat the peanut butter, cream cheese and icing sugar until well combined and creamy. You can add 1-2 tbsp of the whipping cream to achieve a creamy texture.
Whip the cream (or remaining cream) with the vanilla sugar until soft peaks form. Add one third of the whipped cream to the peanut butter mixture to lighten it. Whip it until just well mixed. Fold in the rest of the whipped cream.
Unroll the cake and spread the prepared mousse on top, leaving a 1/2″ border all around to allow the filling to spread a little. Re-roll the cake without the towel and transfer to a serving plate. You can now either dust it with some icing sugar or cover it with a chocolate ganache glaze.
Chocolate ganache glaze
4 oz. good quality dark chocolate
4 oz. cream
1/8 cup icing sugar
2 tbsp butter
2 tsp espresso powder
Melt chocolate and cream in the microwave. Add the remaining ingredients and stir until well mixed. Pour over cake roll.