Clara Bennett This dreamy Nigella Toasted Marshmallow and Rhubarb Cake is made with tender pink forced rhubarb, fresh lemon zest, vegetable oil, and a cloud-like marshmallow icing. The result is a perfect balance of sweet and tart flavors wrapped in a light, toasted meringue finish. This spectacular layer cake makes a stunning centerpiece for a spring celebration or a birthday party.
Nigella Toasted Marshmallow and Rhubarb Cake Ingredients
For the Rhubarb Layer:
- 400g pink forced rhubarb (trimmed weight)
- 100g caster sugar
For the Sponge Cake:
- 6 large eggs, at room temperature (separated into yolks and whites)
- 1 lemon (zested and juiced)
- 100ml full-fat milk, at room temperature
- 150ml vegetable oil, plus extra for greasing
- 150g caster sugar
- 100g plain flour
- 25g cornflour
- 2 teaspoons baking powder
- 1/2 teaspoon bicarbonate of soda
- 1/4 teaspoon fine sea salt
For the Marshmallow Icing:
- 6 egg whites (saved from the eggs above)
- 350g caster sugar
- 1/2 teaspoon cream of tartar (or 1/2 teaspoon lemon juice)
- 1/4 teaspoon fine sea salt
- 2 teaspoons vanilla extract
How To Make Nigella Toasted Marshmallow and Rhubarb Cake
Phase 1: The Rhubarb & Prep
- Roast the rhubarb: Preheat your oven to 200°C (180ºC Fan). Cut the rhubarb into 5cm lengths (or smaller if the stalks are thick). Place them in a single layer in an ovenproof dish. Sprinkle with 100g sugar and mix gently. Cover tightly with foil and bake for about 30 minutes until tender but holding its shape.
- Cool the fruit: Remove the foil and let the rhubarb cool on the counter. It will turn a brighter pink as it cools. Lower the oven temperature to 170°C (150ºC Fan).
- Prepare the pans: Line the bottoms of two 20cm loose-bottomed sandwich tins with parchment paper and lightly grease the sides.
Phase 2: The Cake Batter
- 4. Separate the eggs: Place the egg whites into a large, very clean bowl (for the icing later) and cover them. Place the yolks into a separate mixing bowl.
- 5. Prepare the liquids: Add the lemon zest to the egg yolks. Measure the milk, then add 2 tablespoons of lemon juice to it. Let it sit for a moment to curdle (this creates a quick buttermilk).
- 6. Mix dry ingredients: In a separate small bowl, combine the cornflour, flour, baking powder, bicarbonate of soda, and salt. Set aside.
- 7. Whisk the yolks: Add the 150g sugar and the vegetable oil to the egg yolks. Whisk on medium-high speed for 3 minutes until the mixture is rich, creamy, and looks like mayonnaise.
- 8. Combine the batter: Lower the speed and pour in the curdled milk mixture. Whisk until combined (it will look like custard). Gently fold in the dry ingredients using a spatula just until mixed.
- 9. Bake the cakes: Divide the batter evenly between the two tins. Bake for 20–25 minutes. The tops should be golden and springy to the touch. Let them cool in the tins for 15 minutes, then turn them out onto a wire rack to cool completely.
Phase 3: The Marshmallow Icing & Assembly
- 10. Prepare the water bath: Fill a saucepan with a little water and bring it to a simmer. Combine the reserved egg whites, 350g sugar, salt, and cream of tartar in a heatproof bowl.
- 11. Dissolve the sugar: Place the bowl over the simmering water (don’t let the bowl touch the water). Whisk by hand for 3 minutes until the sugar is dissolved and the mixture is warm.
- 12. Whip the meringue: Remove the bowl from the heat. Whisk with an electric mixer on high speed for 5 to 7 minutes. The mixture will become very thick, glossy, and voluminous. Fold in the vanilla extract.
- 13. Assemble the layers: Place one cake layer on a stand. Spread a thick layer of icing (about 1cm) on top. Arrange the roasted rhubarb over the icing, leaving a small border at the edge. Avoid adding the rhubarb syrup/liquid.
- 14. Frost the outside: Top with the second cake layer. Use the remaining icing to cover the top and sides. Use your fingers to dab and pull the icing to create “spikes.”
- 15. Toast the cake: Using a kitchen blowtorch, carefully toast the top and sides of the meringue until golden brown.
Recipe Tips
- Clean Equipment is Crucial: When whipping egg whites for the icing, your bowl and whisk must be completely grease-free. Even a tiny drop of oil or egg yolk can stop the whites from fluffing up into a meringue.
- The Paper Strip Trick: Before icing the cake, place four strips of parchment paper under the edges of the cake on your stand. Once you finish frosting, gently pull the strips away to leave a clean cake stand with no messy smears.
- Don’t Rush the Cooling: Ensure the cakes are completely cold before you start icing. If the cakes are even slightly warm, the marshmallow icing will melt and slide off.
- Room Temperature Eggs: Cold eggs are harder to separate and don’t whip up as well. Take your eggs out of the fridge 30 minutes before you start baking.
What To Serve Nigella Toasted Marshmallow Cake
This cake is a rich dessert that stands well on its own, but a few simple pairings can elevate the experience.
- Black Coffee or Espresso: The bitterness of strong coffee cuts through the sweetness of the marshmallow icing perfectly.
- Sparkling Wine: A glass of Prosecco or Champagne complements the celebratory look of the cake and the tart rhubarb flavor.
- Fresh Berries: Serve a few fresh raspberries or strawberries on the side to add a fresh texture that contrasts with the soft sponge.
- Mint Tea: A hot cup of fresh mint tea can cleanse the palate after the rich, sugary meringue.
How To Store Cake Leftovers
- Refrigerate: Because of the egg whites in the icing and the fresh fruit filling, this cake is best stored in the refrigerator. Place it in a cake dome or an airtight container. It will last for up to 3 days. Note that the toasted meringue may “weep” (become slightly sticky or watery) the longer it sits.
- Freeze: This cake is difficult to freeze once assembled because the marshmallow icing texture will be ruined by thawing. You can, however, freeze the plain sponge cake layers for up to 1 month before assembling.
Nigella Toasted Marshmallow Cake Nutrition Facts
- Calories: 395 kcal
- Total Fat: 18g
- Saturated Fat: 2.5g
- Cholesterol: 95mg
- Sodium: 180mg
- Total Carbohydrate: 54g
- Dietary Fiber: 1g
- Sugars: 42g
- Protein: 5g
Frequently Asked Questions
- Do I really need a blowtorch? Yes, for the “toasted” flavor and appearance, a blowtorch is necessary. If you don’t have one, you can leave the cake white. Do not try to put the whole cake under an oven broiler, as the cake will melt before it toasts properly.
- Can I make this cake ahead of time? You can bake the sponge layers and roast the rhubarb a day in advance. Store the cakes wrapped in plastic and the rhubarb in the fridge. However, the marshmallow icing should be made and applied on the day you plan to serve the cake for the best texture.
- Why is my icing grainy? If the icing feels gritty between your teeth, the sugar did not fully dissolve during the heating step. Next time, whisk it over the hot water for a minute longer and test it by rubbing a drop between your fingers before moving to the electric mixer.
Try More Recipes:
Nigella Toasted Marshmallow and Rhubarb Cake Recipe
Ingredients
For the Cake:
For the Icing:
Instructions
- Prep Fruit: Roast rhubarb with sugar at 200°C/180ºC Fan for 30 mins. Cool.
- Make Batter: Whisk yolks, oil, and sugar until thick. Add soured milk. Fold in dry ingredients.
- Bake: Bake in two 20cm tins at 170°C/150ºC Fan for 20-25 mins. Cool completely.
- Make Icing: Whisk whites and sugar over simmering water until dissolved. Remove from heat and whip until stiff peaks form. Fold in vanilla.
- Assemble: Layer cake, icing, and rhubarb. Cover the whole cake in remaining icing. Toast with a blowtorch.