Suitable for TM7, TM6, TM5, TM31
Elegant yet wonderfully nostalgic, this berry marshmallow slice is a show‑stopping dessert made for sharing. A light, airy sponge forms the base, topped with fresh strawberries and a cloud‑soft berry cream that sets like marshmallow. Sweet‑tart raspberry coulis runs through the layers, adding colour, contrast and big flavour in every bite. Made almost entirely in the Thermomix, it looks impressive but is surprisingly achievable, with each element prepared step by step before being layered together. Ideal for entertaining, celebrations or make‑ahead dessert tables, this slice slices beautifully and delivers a perfect balance of freshness, sweetness and creamy indulgence.
For more slice recipes, check out our slice recipe collection. For more Thermomix recipes, try these honey crème caramels or chocolate cupcakes.
Ingredients
Method
Sponge cake
Preheat oven to 180°C (fan-forced). Grease and line a rectangular baking tin (20cm x 30cm x 4.5cm) with baking paper.
Insert butterfly whisk. Place egg whites and sugar into mixing bowl and whip 3 min 30 sec/speed 3.5, until stiff.
With butterfly whisk still in place, add egg yolks and mix 15 sec/speed 1. Remove butterfly whisk.
Add bicarb soda, cream of tartar, cornflour, plain flour, vanilla and boiling water, then mix 5 sec/speed 3. Scrape down sides of mixing bowl, then repeat mixing 5 sec/speed 3.
Transfer mixture to prepared baking tin and gently smooth over surface. Bake for 10–15 minutes or until sponge is golden. Set sponge aside in baking tin to cool. Clean and dry mixing bowl and butterfly whisk.
Berry coulis
Place all berry coulis ingredients into mixing bowl and cook 7 min/90°C/speed 4. Strain coulis into a bowl through a fine-mesh sieve and set aside. Discard pips in sieve.
Berry cream
Place gelatine leaves into a bowl and cover with chilled water. Set aside to soak until needed.
Place 250g of the berry coulis into mixing bowl and heat 2 min/60°C/speed 2.
Gently squeeze excess water from gelatine leaves. Add gelatine leaves to mixing bowl and mix 20 sec/speed 3, or until gelatine dissolves. Transfer berry-gelatine mixture to a bowl and set aside to cool. Cover remaining berry coulis and refrigerate until ready to serve. Clean and dry mixing bowl.
Re-insert butterfly whisk. Place cream into mixing bowl and whip speed 3 until soft peaks form, stopping time to check and avoid overwhipping. Remove butterfly whisk.
Spoon a thin layer of the whipped cream (approximately 100g) on top of the sponge cake in baking tin and spread evenly with spatula. Arrange strawberries, cut-side down in neat rows on top of the cream.
Add reserved berry-gelatine mixture to remaining cream in mixing bowl and mix 10 sec/speed 2. Scrape down sides of mixing bowl, then repeat mixing 10 sec/speed 2.
Carefully spread berry cream over the top of strawberries, then refrigerate to chill for 1 hour.
Dot berry coulis over slice, then cut into slices and serve.
TIP
The time it takes to whip cream depends on the temperature of the ingredients and the fat content of the cream – the more fat it contains, the easier it is to whip and the stiffer the consistency it will achieve. The optimum temperature is 4-6°C. For better results, you can cool the mixing bowl.
This is an edited extract from ‘Thermomix 25th Anniversary Magazine’, issue 5, 2026 – The Collector’s Edition, $14.99.
