The first time I attempted Mary Berry’s rainbow cake, I seriously considered giving up halfway through. I had optimistically thought, “How tricky can it be to bake a few colourful layers and add some frosting?” Oh, how naïve I was.
By the third layer, things were already going sideways. One came out dry as a biscuit, another turned a swampy shade of green thanks to a colouring misjudgment, and I discovered—too late—that my fridge couldn’t fit the fully assembled cake.
Still, I pushed through—and I’m so glad I did. Once you settle into the rhythm of baking, cooling, and repeating, it all starts to click. The final result? A true showstopper. But more importantly, it tastes every bit as amazing as it looks. Let me share what I learned the hard way, so your masterpiece doesn’t resemble a wobbly Leaning Tower of Rainbow.
What Makes This Recipe Special
Sure, the colours are fun—but that’s not what sets this rainbow cake apart. The real magic lies in the sponge. It’s light yet sturdy enough to support six vibrant layers without collapsing into a sugary mess. Paired with a tangy cream cheese frosting, it strikes a perfect balance between sweet and satisfying.
Unlike most rainbow cakes, which often sacrifice flavour and texture for visual appeal, Mary Berry’s version delivers on all fronts. It’s fluffy, flavourful, and surprisingly forgiving—even if you forget to level one of the layers (guilty as charged).
And here’s a pro tip: using buttery spread straight from the fridge is a total game-changer. It creams beautifully without the hassle of waiting for it to soften.
Ingredients & Why They Matter
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Buttery spread (375g) – Surprisingly easy to work with cold. It gives the sponge a soft, tender crumb without making it greasy. I tried regular butter once—too stiff and tricky to mix.
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Eggs (6 total) – Essential for structure and richness. Let them come to room temperature so they blend more smoothly.
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All-purpose flour (375g) – Provides the necessary stability for stacking. Avoid self-raising flour—it throws off the texture due to the extra leavening.
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Gel food colouring – Use gel or paste for bold, vibrant hues. Liquid food colouring can thin the batter and bake into dull tones.
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Full-fat cream cheese (275g) – No low-fat substitutes here—it’ll make your frosting runny and disappointing.
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Confectioners’ sugar (750g) – Sift it! Lumpy frosting is nearly impossible to rescue once it’s mixed.
Making It Yours (Without Ruining It)
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Egg-free? I’ve tested it with an egg replacer—it worked, but the texture was a bit gummy. You’re better off using a dedicated eggless sponge recipe and colouring that.
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Gluten-free? I haven’t fully tested this version, but a 1:1 gluten-free flour blend should work. Just expect a more delicate crumb.
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Prefer pastel layers? Use less food colouring gel for a softer, spring-like palette instead of bold rainbow stripes.
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No cream cheese on hand? Go with classic buttercream. Add a pinch of salt and a splash of lemon juice to cut the sweetness.
| What Went Wrong | Why It Happens | How to Fix It |
|---|---|---|
| Uneven layers | Eyeballing the batter amounts | Weigh the batter for each colour |
| Layers dried out | Overbaked by even 2–3 minutes | Check at 13 mins, not just 15 |
| Frosting turned soupy | Used low-fat cream cheese | Only use full-fat, and beat it cold |
| Cake leaned sideways | Stacked on a slanting board | Level layers + use a spirit level |
How to Make Mary Berry’s Rainbow Cake
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Prep Your Tins
Preheat the oven to 180°C (160°C fan). Grease and line two 8-inch round cake tins. You’ll be baking in batches, so keep these tins ready for re-use. -
Make the Batter
In a large bowl, beat the buttery spread and sugar together until light and fluffy. Add the eggs one at a time, mixing well after each addition. Sift in the flour, baking powder, and salt. Stir in the vanilla extract and milk until smooth. -
Divide and Colour
Weigh your total batter and divide it evenly into six bowls. Tint each batch with gel food colouring, using a cocktail stick to add colour gradually until you get your desired shades. -
Bake in Batches
Bake two coloured layers at a time for about 15 minutes, or until a skewer comes out clean. Transfer to wire racks to cool. Don’t forget to re-grease and re-line your tins before each batch. -
Make the Frosting
Beat the butter and milk with half the confectioners’ sugar until smooth. Add the remaining sugar, vanilla, and cold full-fat cream cheese. Beat just until the frosting is fluffy—overmixing can make it loose. -
Assemble the Layers
Starting with violet and working up to red, stack the cake layers with a thin layer of frosting in between each. Apply a light crumb coat over the entire cake to seal in loose crumbs. -
Chill
Refrigerate the cake for about 20 minutes to let the crumb coat firm up. -
Final Frost and Decorate
Apply a smooth final coat of frosting using a cake scraper. Finish with a generous sprinkle of nonpareils or your choice of decorations.
