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)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 390 kcal
- Protein
- 9 g
- Carbohydrates
- 35 g
- Fat
- 25 g
- Fiber
- 1 g
- Sugar
- 32 g
- Sodium
- 99 mg
- Saturated Fat
- 8 g
- Monounsaturated Fat
- 6 g
- Polyunsaturated Fat
- 10 g
- Cholesterol
- 238 mg
- Potassium
- 174 mg
- Calcium
- 52 mg
- Iron
- 1.2 mg
- Magnesium
- 35 mg
- Phosphorus
- 155 mg
- Zinc
- 1.1 mg
- Vitamin A
- 144 mcg
- Vitamin C
- 9 mg
- Vitamin D
- 1.1 mcg
- Vitamin E
- 0.9 mg
- Vitamin K
- 1 mcg
- Vitamin B6
- 0.2 mg
- Vitamin B12
- 0.4 mcg
- Thiamin
- 0.11 mg
- Riboflavin
- 0.25 mg
- Niacin
- 0.3 mg
- Folate
- 53 mcg
- Water
- 47 g
Sources: USDA FoodData Central
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.
Troubleshooting
Sponge cracks heavily when rolling
Cause: Sponge was overbaked or allowed to cool flat before rolling
Fix: Press gently together and cover the outside of the finished roll with powdered sugar, whipped cream, or a glaze to hide cosmetic damage
Prevention: Ensure you roll the sponge immediately out of the oven while the steam makes it pliable
Curd is grainy or contains white bits
Cause: Heat was too high causing the egg proteins to scramble
Fix: Straining through a fine mesh sieve will catch most coagulated egg bits
Prevention: Keep heat low and whisk continuously, ensuring it does not reach boiling point
Curd is running out of the sides of the roulade
Cause: Curd was not chilled completely before assembly or undercooked
Fix: Wrap the assembled roulade tightly in plastic wrap and freeze for 30 minutes to firm up the filling before slicing
Prevention: Cook curd until it reaches 76C and chill until completely firm before spreading
Cultural Context
Flourless nut sponges are a hallmark of Central European baking traditions, particularly in Austria and Hungary where walnuts have historically been an abundant local crop. Combined with vibrant winter citrus like blood orange, this dessert marries rich, earthy foundational flavors with bright, seasonal acidity, creating a visually striking and historically rooted festive centerpiece.
