WHAT YOU NEED

For the miso caramel
175g double cream
21⁄2 tbsp miso
175g caster sugar
75g water

For the white chocolate mudcake
150g unsalted butter
100g white chocolate chips, plus 75g finely chopped
120ml milk
1⁄4 tsp vanilla extract
a pinch of sea salt
120g caster sugar
2 eggs
180g self-raising flour

For the miso caramel buttercream
200g unsalted butter, softened
320g icing sugar, sifted

For the white chocolate & sesame decorations
100g white chocolate
1 tbsp black sesame seeds

For the black ganache
100g dark chocolate chips (54% cocoa solids)
100g double cream
1 tbsp black cocoa powder

To make the miso caramel
Measure the cream into a jug and have it ready nearby, along with the miso.
In a medium saucepan, combine the sugar and the water, giving it a little bit of a stir to ensure that all the sugar is evenly soaked. Bring the mixture to a simmer over a low–medium heat and, without stirring at all (no matter how tempting), allow to bubble away for a few minutes until it begins to colour. Keep your eye on it and let it bubble away until it becomes a beautiful rich amber colour.
When the caramel has reached optimum amber, take it off the heat and add the cream, bit by bit, stirring quickly and carefully. Remember this is incredibly hot! Once all of the cream has been stirred in, add the miso and stir until completely dissolved.
Leave to cool completely, then pop it in the fridge.

To make the white chocolate mudcake
Preheat your oven to 190°C (170°C fan) and line a 12-hole cupcake tin with paper cases.
In a small saucepan over a low heat, melt together the butter, 100g of white chocolate, milk, vanilla, and salt, stirring occasionally to make sure it doesn’t catch and burn on the bottom of the pan. Leave to cool for 5 minutes or so.
In a large mixing bowl, whisk together the sugar and eggs until pale and a bit fluffy. Pour in the white chocolate mixture and whisk to combine.
Add the flour and whisk until you have a smooth, lump-free batter, then add the remaining 75g finely chopped white chocolate and stir to combine.
Distribute the batter among the paper cases until they are three-quarters full, then bake for 18–20 minutes or until a toothpick inserted into the centre comes out clean Leave to cool.

To make the miso caramel buttercream
In a stand mixer fitted with the paddle attachment, or a large mixing bowl, beat the butter for at least 5 minutes on a high speed until it has turned almost white in colour and is nice and whippy. Add half of the sifted icing sugar and beat for 3–5 minutes, then repeat with the remaining icing sugar. You should have a very pale, almost white buttercream that is a bit too stiff. Add half of the miso caramel you made earlier and beat it in thoroughly. Make sure you taste it and add a bit more caramel if you want a stronger miso flavour.

To make the white chocolate & sesame decorations
Line a baking sheet with greaseproof paper or a silpat. Melt the white chocolate as described on page 112, then pour it onto the prepared baking sheet and spread it out evenly using a palette knife or spatula until about 2mm thick. While it is still wet, sprinkle the black sesame seeds evenly over the top. If your chocolate is tempered, it will begin to set pretty quickly. If you haven’t tempered it, that’s okay, just pop it in the fridge for a bit to allow the chocolate to firm up. When it’s almost set, use a round cookie cutter (3–4cm is a good diameter) to cut the discs, then leave to set completely before removing them.

To finish
Remove the centres of your cupcakes using an apple corer (do not throw these away, they can be used as bribes for your children, or snacks for yourself!). Put the remaining miso caramel into a piping bag and fill the cupcakes holes with it. Pop the buttercream into a piping bag with a large round nozzle and pipe a generous blob on top of each cupcake. Pop them into the fridge for 10–15 minutes while you make the black ganache. Make a dark chocolate ganache, then sift in the black cocoa powder and stir it all to completely combine. Remove the cupcakes from the fridge and, turning each one upside down, dip them into the black ganache until it reaches halfway up the sides of the icing. Leave to set for a couple of minutes before topping each cupcake with a sesame and white chocolate disc.