The mayo gives this cake extra richness and adding it to the frosting as well gives it a luxuriously silky texture. Blond chocolate (essentially caramelised white chocolate) gives the frosting a lovely toasty flavour.
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Yields:
16 serving(s)
Prep Time:
40 mins
Cook Time:
1 hr
Total Time:
1 hr 40 mins
Cal/Serv:
422
Ingredients
200g
unsalted butter, softened, plus extra to grease
75g
cocoa powder
200g
dark brown soft sugar
150g
caster sugar
3
medium eggs
50g
mayonnaise, we used Heinz Seriously Good
300g
self-raising flour
For the frosting
150g
sweetened condensed milk
50g
dark brown soft sugar
75g
blond white chocolate, roughly chopped, we used Cadbury Caramilk
150g
unsalted butter, softened
3Tbsp.
mayonnaise
Directions
Step 1Preheat oven to 180°C (160°C fan) mark 4.
Grease a 20.5cm square
tin (that’s at least 5cm
deep) and line with
baking parchment. In
a large heatproof jug,
whisk the cocoa powder
and brown sugar with
200ml just-boiled water
until smooth.
Step 2In a large bowl, using a
handheld electric whisk,
beat the butter and
caster sugar until light
and fluffy. Add the eggs
one at time, followed by
the mayonnaise, beating
well after each addition.
Beat in a little of the flour
if the mixture looks like it
might curdle.
Step 3Add 1/2 the (remaining)
flour and beat to
combine, followed
by 1/2 the cocoa mixture,
until just combined.
Repeat with remaining
flour and cocoa mix.
Scrape batter into tin
and smooth to level.
Bake for 45-50min, or
until springy to the touch
and a skewer inserted
into the centre comes
out clean. Leave to cool
completely in the tin.
Step 4Meanwhile, for the
frosting, in a medium
pan over low heat, stir
the condensed milk and
sugar until melted and
combined. Stir in the
chocolate to melt.
Remove from the heat,
scrape into a bowl and
leave to cool at room
temperature, uncovered,
stirring occasionally (it
will thicken on cooling).
Step 5Beat the butter
and mayonnaise in
a large bowl, using a
(clean) handheld
electric whisk, until
light and fluffy. Add
the cooled chocolate
mixture and beat
well to combine.
Chill until needed.
Step 6Transfer cake to
a board and spread
over the frosting.
Serve in squares.
Blond chocolate (essentially caramelised white chocolate) gives the frosting a lovely toasty flavour, but you could swap for regular white chocolate if you prefer.
To make your own caramelised white chocolate, check out our handy guide.
An experienced and highly skilled team of food writers, stylists and digital content producers, the Good Housekeeping Cookery Team is a close-knit squad of food obsessives. Cookery Editor Emma Franklin is our resident chilli obsessive and barbecue expert, who spends an inordinate amount of time on holidays poking round the local supermarkets seeking out new and exciting foods. Senior Cookery Writer Alice Shields is a former pastry chef and baking fanatic who loves making bread and would have peanut butter with everything if she could. Her favourite carb is pasta, and our vibrant green spaghetti is her weeknight go-to. Lover of all things savoury, Senior Cookery Writer Grace Evans can be found eating crispy corn and nocellara olives at every opportunity, and will take the cheeseboard over dessert any time (though she cannot resist a slice of tres leches cake). With a wealth of professional kitchen know-how, culinary training and years of experience between them, they are all dedicated to ensuring every Good Housekeeping recipe is the best it can be, so you can trust they’ll work (and if they don’t – we’ll have the answer for why*) every time (*90% of the time the answer is: “buy an separate oven thermometer”!).
Alice Shields is Senior Cookery Writer for Good Housekeeping. A trained pastry chef, you’ll find her food styling on photo shoots, developing delicious recipes and writing about all things food. She loves to bake and her favourite pudding will always be a chocolate fondant. Originally hailing from Lancashire, she finally achieved her goal of getting a butter pie recipe into the magazine.
