Anne Morgan Here is the Delia Smith mashed potato chocolate cake recipe, her Chocolate ‘Surprise’ Cup Cakes, which makes 12. You melt dark chocolate with butter, sugar and condensed milk, then whisk it into flour, an egg and 110g of mashed potato. They bake in about 15 minutes, so allow 40 minutes in all with the icing.
The mashed potato is the hidden ingredient, and Delia says it gives the little cakes a soft, moist texture. The recipe comes from Delia’s Cakes (2014), and her website chose it as its Cake of the Week in July 2026.
She points out that bakers often use mashed potato in potato scones, but she finds it even better in these small cakes. A level teaspoon of Chinese five spice adds a gentle warmth.
Leftover mash from her mashed potato recipe works too, with or without its butter and milk.
Delia Smith’s Chocolate Surprise Cupcakes
Course: DessertCuisine: BritishDifficulty: Easy12
servings15
minutes25
minutes230
kcalLittle dark chocolate cakes made moist with mashed potato and a hint of five spice, topped with melted chocolate icing and chocolate buttons.
Ingredients
- For the cakes:
75g dark chocolate (minimum 70% cocoa solids)
50g condensed milk
75g block butter
110g mashed potato (it can be frozen and defrosted)
110g self-raising flour, sifted
1 level teaspoon baking powder
1 large egg
1 level teaspoon Chinese five spice powder
- For the dark chocolate icing:
50g dark chocolate
100g condensed milk
10g block butter
24 pink chocolate buttons
two 6-cup muffin trays, lined with paper fairy cake cases
Directions
- Oven: Heat the oven to 180°C, gas mark 4. Line the muffin trays with the paper cases.
- Melt: Break the chocolate into a medium heatproof bowl and add the condensed milk, sugar and butter. Set it over a pan of barely simmering water, not touching the water. Let it melt on the lowest heat for about 6 minutes, with the odd stir.
- Mix: Meanwhile, put the mashed potato, flour, baking powder, egg and five spice in a large bowl. Add the melted chocolate mixture and whisk until smooth and creamy.
- Bake: Divide the mixture between the paper cases and bake near the centre of the oven for about 15 minutes. Let them cool in the tin.
- Icing: Melt the icing chocolate with the condensed milk in the same way. Take it off the heat, stir in the butter until melted, then leave it to cool for about 5 minutes.
- Finish: Spread the icing over the cakes with a small palette knife and top each one with two chocolate buttons. Store them in an airtight tin.
Notes
- Weigh the mashed potato after it has defrosted, and break up any lumps with a fork before it goes in, my own tip.
FAQs
Can I use frozen mash?
Yes, Delia says frozen mashed potato works really well for this, once it has defrosted. You need 110g for 12 cakes.
Her website adds that fresh or frozen mash both work, with or without milk, butter and salt. So a spoonful of leftover mash from dinner is fine.
Can I leave out the five spice for children?
Yes, Delia says you may like to leave the spice out for children. She also knows a five-year-old who loves its subtle spiciness.
The five spice gives a gentle warmth that goes well with the dark chocolate, my own view.
Which chocolate should I use?
Use dark chocolate with at least 70% cocoa solids for the cakes. For the icing, Delia gives a choice of dark, milk or white chocolate.
For a milk chocolate icing, melt 75g milk chocolate, with at least 30% cocoa solids, with 75g condensed milk. Top each cake with white chocolate buttons.
For a white chocolate icing, melt 75g white chocolate with 75g condensed milk and top with milk chocolate buttons. Each icing takes 10g block butter, and the dark one on the card uses 100g condensed milk, the most of the three.
How do I melt chocolate without it going grainy?
Melt it slowly in a heatproof bowl set over barely simmering water, as Delia does, with the bowl clear of the water. Keep the heat at its lowest and stir only once in a while.
Water or steam in the chocolate can make it thick and grainy, so dry the bowl and spoon well first, my own tip.
How long do the cupcakes keep?
Keep them in a tin with a tight lid, as Delia does. I’d eat them within 3 days, while they are still soft and moist, my own tip.
