My Dream Layer Cake

Milk Chocolate Tahini Layer Cake

Hello! Happy Friday.

Todays newsletter is going to be a little different. I am taking a deep dive into the archive to unearth a recipe from the early days of this newsletter, before I moved to substack, before most of you were subscribed. I am visiting the archives for a very special reason. My partner became an uncle for the first time this week so we quickly left London and headed to the south coast to visit family and to meet our gorgeous nephew. I apologise but holding and cooing over newborn babies came first this week. I will be back next week with a brand new fabulous recipe, so I hope you enjoy this delicious cake until then.

The recipe is for a brilliant milk chocolate and tahini layer cake. The chocolate cake is a classic devils food affair with a little rye flour thrown in for a little extra flavour. The cake is layered with a simple milk chocolate ganache and some of the tahini buttercream. And the buttercream is where things get interesting. It’s made with a style of buttercream that is a little less common but one that deserves to be more popular because it is truly wonderful. The style is known by a few different names including German Buttercream, Custard Buttercream and Creme Mousseline. The name second name should give you a good clue as to how its made, it’s basically a pastry cream whipped into butter to make a light and fluffy buttercream. The reasons I like it are thats it’s incredibly smooth and creamy, less sweet than other varieties and can be infused with flavours very easily. In this case I made a tahini version for a delicious nutty buttercream.

Chocolate Cake

85g unsalted butter, diced

100g dark chocolate (65-75% cocoa solids), roughly chopped

185g plain flour

75g wholemeal rye flour

1 tsp baking powder

2 tsp bicarbonate of soda

1/2 tsp fine sea salt

275g light brown sugar

50g cocoa powder

200ml hot black coffee

225ml buttermilk

2 large eggs

Milk Chocolate Filling

125g milk chocolate, roughly chopped

125ml double cream

Tahini German Buttercream

225ml whole milk

200g caster sugar

15g cornflour

2 large eggs

1 tsp vanilla bean paste

375g unsalted butter, room temperature

75g tahini

Before you make the cake it is worth preparing the custard base for the buttercream. Place the milk and half of the sugar into a saucepan and bring to a simmer. Meanwhile place the remaining sugar, cornflour and eggs into a medium bowl and whisk together until smooth. Add the vanilla and whisk to combine. When the milk is at temperature pour slowly into the eggs, whisking to combine and to prevent scrambling. Scrape this custard mixture back into the saucepan and whisk over medium/high heat until the mixture thickens. With the mixture bubbling cook for a further minute, to cook out the cornflour, and then immediately scrape into a clean bowl. Press a sheet of clingfilm onto the surface of the custard and refrigerate until fully chilled, at least four hours. Normally I make this element the day before.

When making German Buttercream, because it’s milk based, you can also infuse a lot of flavour into the milk before making the base. You could add some spices, tea, coffee etc to the milk and bring to a simmer before setting aside for an hour to infuse then straining and continuing as above.

To make the cake heat the oven to 180C (160C fan) 350F and lightly grease two deep 8 inch round cake tins and line the bases with parchment paper.

Put the butter and chocolate into a small heatproof bowl over a pan of simmering water and heat until melted. Alternatively, put the bowl in the microwave and melt, heating on bursts of no more than 30 seconds to prevent the chocolate burning. Take the bowl from the heat and set aside.

In a large bowl, sift in the flours, baking powder, bicarb, salt and brown sugar – the sifting will help to break up any lumps in the sugar. Put the cocoa powder in a jug and pour over the hot coffee, whisking to prevent lumps. Pour the coffee mixture, buttermilk, eggs and chocolate mixture into the flour bowl, and whisk to form a smooth batter. Divide the batter evenly between the tins and bake for 25-30 minutes or until the cakes spring back to a light touch or a skewer inserted in the middles comes out clean. Allow to cool in the tins for 10 minutes before inverting onto a wire rack to cool completely.

For the filling finely chop the chocolate and place into a small bowl. Bring the cream to a simmer (this can be done in a microwave or set over a pan of simmering water) and pour it over the chocolate, setting aside for a couple minutes, before stirring to form a silky smooth ganache. Refrigerate the ganache until has thickened and is spreadable.

For the buttercream you need to remove the pastry cream an hour before you make the buttercream, to remove the chill and bring it to room temperature, you also want to give it a bit of a beat with a spatula to loosen it and remove any lumps. Place the butter into a large bowl and using an electric mixer beat on medium speed until the butter is light and creamy, this should take about 3 minutes. Slowly add the pastry cream base, whilst the mixer is still running, a spoonful or so at a time until all has been added. Continue beating the buttercream until the texture is similar to a meringue based buttercream. Scrape in the tahini and beat until fully combined.

Buttercream Troubleshooting

If the buttercream is too loose you can refrigerate it for a short amount of time and then rewhip it. If the butter and pastry cream are too cold the mixture can sometimes have problems combining and look a little separated. If this happens you can use a kitchen blowtorch to gently heat the bottom of the bowl, being very careful to just add a little warmth, mixing until everything is smooth and silky. With this buttercream the main thing to watch out for is temperature, if the butter and pastry cream are too far apart in temperature you are likely to run into issues with separation.

Assembly

To assemble the cake place one of the layers onto a cake board or stand and spread over the ganache. Top with a thin layer of buttercream and sandwich with the second cake layer. Scrape the remaining buttercream on top of the cake and spread over the top and sides of the cake. To decorate I took the last little bit of buttercream and piped small rounds of buttercream around the edges of the cake and sprinkled with sesame seeds.

Kept covered this cake will keep for 2-3 days.