A recent taste test of supermarket party cakes has revealed that even premium options are laden with emulsifiers, preservatives, and stabilisers, placing them firmly in the ultra-processed food category. The review, conducted by a food critic, evaluated nine cakes based on appearance, taste, texture, value, certifications, animal welfare, and total sugar content.
Ultra-Processed Ingredients Across the Board
Despite claims of being "handmade" with "carefully selected high-quality ingredients," all cakes contained additives. Premium cakes included emulsifiers such as mono- and diglycerides of fatty acids, polyglycerol esters, and sodium stearoyl-2-lactylate, along with preservatives, stabilisers, synthetic raising agents like diphosphates, and glucose-fructose syrup, a heavily processed industrial sweetener linked to metabolic concerns. The number of additives per product ranged from five to twelve, excluding natural colours, flavourings, pectin, citric acid, carbonates, bicarbonate of soda, beeswax, and glucose syrup.
Best Overall: Waitrose Over the Rainbow Cake
The Waitrose Over the Rainbow Cake (£18 for 1.28kg, serving 16) scored four out of five stars. Described as a deep, 15cm-diameter, 9cm-high cake with light purple, orange, and yellow layers, it features a vanilla buttercream made with real vanilla extract, a soft and moist sponge, and total sugars of 39.2%. It contains eight additives, including four emulsifiers and glucose-fructose syrup, but is made with free-range eggs, unsalted butter, and is palm oil-free.
Best Bargain: Asda Rainbow Jazzie Cake
The Bakery at Asda Rainbow Jazzie Cake (£15 for 1.3kg, serving 20) earned two stars. This large cake has magenta, yellow, and carrot-coloured layers, a fluffy sponge, and classic sweet icing described as greasy, flavourless, and bland. It contains six additives, including palm oil and carminic acid (a red colouring from cochineal), and has the lowest total sugars at 33%. It is not suitable for vegetarians.
Other Notable Cakes
M&S Rainbow Layer Cake (£20 for 900g, serving 8) received four stars for its five tiers of pastel sponge with Madagascan vanilla buttercream, 41.6% sugars, and only five additives, with no palm oil, preservative, or glucose-fructose syrup. Lola's Vanilla Layer Cake (£27.50 for 660g, serving 8) scored three stars, featuring a tart compote centre, 43.4% sugars, and 12 additives including titanium dioxide (banned in the EU since 2022) and propylene glycol. Fiona Cairns Mini Pink Boutique Cake (£9 for 290g, serving 4) also scored three stars, with a moist sponge, raspberry jam, 44% total sugars (the highest in the test), and 10 additives.
Mid-Range and Low Performers
Sainsbury's Taste the Difference Rainbow Layer Cake (£18.50 for 685g, serving 10) earned three stars, with a tall cake featuring six additives and 42.1% sugars. Lidl Rowan Hill Bakery Madeira Party Cake (£4.79 for 888g, serving 16) scored two stars, with eight additives and 40.3% sugars. Tesco Vanilla Party Cake (£10 for 976g, serving 16) also scored two stars, with 10 additives and 42.4% sugars. Morrisons Sprinkle Cake (£15 for 1.425kg, serving 20) scored two stars, with nine additives and 42.5% sugars. The lowest-rated was Aldi Village Bakery Party Cupcake Platter (£4.49 for 12 cupcakes), scoring one star, with 10 additives and 41.6% sugars, and icing described as having a synthetic, gummy texture.
