Equipment
Ingredients
Walnut Sponge
- 150 g walnuts, finely ground
- 5 egg yolks, room temperature
- 5 egg whites, room temperature
- 120 g caster sugar
- 1 g salt
Blood Orange Curd
- 100 ml blood orange juice, freshly squeezed
- 10 g blood orange zest, finely grated
- 15 ml lemon juice, freshly squeezed
- 3 egg yolks
- 1 whole egg
- 100 g caster sugar
- 75 g unsalted butter, cubed and softened
Assembly
- 20 g powdered sugar, sifted
Nutrition (per serving)
Method
Preheat the oven to 180°C/350°F. Line a 25 by 38 centimeter jelly roll pan with parchment paper.
In a mixing bowl, beat the 5 egg yolks and half of the caster sugar until pale, thick, and ribbon-like.
In a separate clean mixing bowl using a stand mixer, whip the 5 egg whites and salt to soft peaks. Gradually add the remaining caster sugar and whip until stiff but not dry peaks form.
Gently fold the finely ground walnuts into the egg yolk mixture using a spatula.
Carefully fold the whipped egg whites into the walnut mixture in three separate additions to keep the batter light and airy.
Spread the batter evenly into the prepared jelly roll pan. Bake for 12 to 15 minutes until the sponge springs back when lightly touched.
Generously dust a clean kitchen towel with powdered sugar. Immediately invert the warm sponge onto the towel, carefully peel off the parchment paper, and roll the sponge up tightly with the towel inside. Let it cool completely in this rolled position.
To make the curd, whisk the blood orange juice, blood orange zest, lemon juice, 3 egg yolks, whole egg, and caster sugar in a saucepan.
Place the saucepan over low heat and simmer, stirring constantly with a whisk, until the mixture thickens heavily and coats the back of a spoon, reaching approximately 76°C/170°F. Ensure it does not boil to prevent scrambling the eggs.
Remove the saucepan from the heat and pass the warm curd through a fine mesh sieve into a clean bowl.
Whisk the softened unsalted butter into the warm strained curd one piece at a time until fully emulsified and smooth.
Cover the curd with plastic wrap pressed directly onto the surface to prevent a skin from forming, and chill in the refrigerator for at least 1 hour until firm.
Carefully unroll the cooled walnut sponge. Spread the chilled blood orange curd evenly over the inside surface, leaving a small clean border around the edges.
Roll the sponge up again, this time without the towel. Wrap the finished roulade tightly in plastic wrap and chill for at least 1 hour to set its shape before serving.
Chef's Notes
- Whipping the egg whites to stiff but not dry peaks is crucial. Overwhipped whites lose their elasticity, increasing the likelihood that your sponge will crack during the rolling phase.
- Blood orange juice can sometimes lack the punchy acidity of standard lemons or oranges. Adding a splash of fresh lemon juice elevates the curd, preventing the dessert from tasting flat or overly sweet.
- Always roll the sponge while it is piping hot from the oven. The ambient steam trapped by the kitchen towel helps the cake memorize the rolled shape without breaking.
- Straining the blood orange curd through a fine mesh sieve before adding the butter is a professional safeguard that guarantees a flawlessly silky texture by removing stray zest and any accidentally cooked egg chalazae.
Storage
Refrigerator: 3 days — Keep tightly wrapped in plastic wrap to prevent the sponge from drying out.
