This easy Chocolate & Lime Roll cake is made from a light, flourless chocolate sponge brushed with lime syrup, filled with lime-spiked whipped cream and coated in a rich chocolate ganache for the ultimate gluten-free dessert.
For the Chocolate Sponge
- 6 large eggs, separated
- 150g (6 oz) golden caster (granulated) sugar
- 2 tsp vanilla extract
- 50g (2 oz) cocoa powder
For the Chocolate Lime Roll
- 2 limes
- 1 tbsp golden caster (granulated) sugar
- 300ml (1 1/4 cups) whipping cream (heavy cream)
- 1 tsp icing (confectioners) sugar
- 100g (3.5 oz) dark chocolate
- Pre-heat the oven to 180 degrees (355 fahrenheit) and line a large swiss roll tin with baking parchment.
- In a stand mixer fitted with the balloon whisk attachment, whisk the egg whites until they are thick and frothy. Make sure the bowl of the mixture and your whisk are very, very clean, otherwise the eggs may not thicken properly. If you’re not sure, wipe your bowl out with a bit of lemon juice or white wine vinegar.
- Add 50g (2 oz) of the caster sugar, and whisk until the mixture is thick, glossy and holds stiff peaks.
- In a separate bowl, using a hand held electric whisk set on high, whisk together the egg yolks and the remaining sugar until the mixture is thick and pale. Whisk in the vanilla extract. Fold in in the cocoa powder with a metal spoon until the mixture is consistent.
- Add a few generous spoonfuls of the whisked egg whites into the chocolate mixture, and gently fold them in. Then, fold in the rest of the egg white in manageable amounts until the mixture is uniform, doing your best to keep as much of the air in as possible.
- Pour the mixture into the prepared tin, making sure the top is smooth and it is pushed right into the corners. Cook in the oven for 20 minutes.
- Allow the sponge to cool in the tin for 10 minutes or so until it is cool enough to touch, then slide it out, greaseproof paper side down, onto a wire rack.
- Meanwhile, zest the limes and set the zest aside. Combine the juice of the limes with the 1 tbsp of sugar in a small saucepan. Set over a medium heat and stir until the sugar has dissolved. Set aside.
- While the sponge is cooling, brush the exposed side with the lime syrup.
- To make the cream filling, whip together 200ml (3/4 cups) of the cream with the icing sugar until starting to thicken. Add most of the zest, setting a little aside for decoration, and beat until it just holds it’s shape.
- Once the sponge is cool, place a piece of baking parchment over the syrup side of the sponge and place the cutting board over the top. Holding the board onto the cooling wrack with the sponge trapped inside, flip it, remove the wrack, and carefully peel off the paper, easing the edges first to try and not break the sponge. Replace the paper and flip again.
- Using a palette knife, carefully spread the whipped cream over the syrup side of the sponge, being careful not to catch the sponge to pick up any crumbs.
- Working with the slim side of the sponge in front of you, paying attention to support the sponge to reduce any cracks, roll the roll away from you, leaving it to rest seam side down. Refrigerate while you make the ganache.
- To make the chocolate ganache, break the chocolate up into small pieces and combine with the remaining cream in a heatproof glass bowl. Set the bowl over a saucepan of simmering water set over a medium heat, making sure the water is not touching the bottom of the bowl. Stir occasionally until the chocolate has just melted into a smooth ganache.
- Smooth the ganache over the roll, taking care to fill in any cracks. Decorate the top with the reserved lime zest, and if you need to transfer it to a serving platter, chill for a little longer in the fridge to set the ganache to make things neater when you lift it with a clean palette knife.