Plum and Lime Layer Cake

Layers of fluffy buttermilk cake, sweet plums, and tangy lime curd make this a lovely pink cake. There are two possibilities for a two-layer or four-layer cake.

Ingredients

850 g/30oz tin black Doris plums
2 Tbsp caster sugar

For the cake:

1 3/4 cups plain all-purpose flour
3 1/2 tsp baking powder
1/2 tsp sea salt
1 cup buttermilk
1 tsp vanilla extract or paste
125 g/1 stick unsalted butter, softened
1 cup caster sugar
3 free-range eggs

For the frosting:

200 g/7oz unsalted butter, softened
4 cups icing sugar

To assemble:

6 Tbsp lime curd either homemade, see note 1, or store bought

Instructions

Preheat oven to 180C/350F.

For the plums:

Open the plum can. Set aside half of the plums (6) in a small dish. These are going to be utilized in the cake. Sprinkle 2 tbsp caster sugar over the remaining plums and liquid from the pan in a baking dish. Preheat the oven to 400°F and bake for 40 minutes (see note 2). Allow to cool to the point where you can handle it. Remove the stones from the plums and puree the plum flesh and juice until smooth in a blender or food processor. Allow to cool completely before using. Reserve 4 tablespoons for the frosting; the remainder may be stored in the refrigerator and used over ice cream, oatmeal, cereal, or a pavlova.

For the lime curd:

While the plums are baking, create your lime curd by replacing lemons for limes in my Homemade Lemon Curd recipe. You may also buy a jar of excellent quality lime curd or even lemon curd. Only 6 tablespoons are needed for the cake; the remainder can be used in other cakes, ice cream toppings, meringues, or wonderful small tarts.

For the cake:

Grease and line 2 x 15cm/6in round cake tins (or 2 x 20cm/8in round cake tins) for a four-layer cake (or 2 x 20cm/8in round cake tins for a two-layer cake).
Combine the flour, baking powder, and salt in a small mixing dish. Remove from the equation.
Combine the buttermilk and vanilla in a separate small bowl.
In the bowl of a standing mixer fitted with a paddle attachment, cream together the 125g/1 stick butter and 1 cup caster sugar for about 5 minutes, or until light and fluffy. One at a time, add the eggs, ensuring that they are fully integrated after each addition. If the mixture appears to have curdled, simply stir in a tablespoon of the flour mixture.
1/3 of the flour mixture should be added and mixed well. Then add half of the buttermilk mixture, the second third of the flour mixture, half of the buttermilk, and the last third of the flour mixture. Make sure the ingredients are well blended, but don’t overmix.
Divide the batter evenly between the baking pans. Remove the stones from the saved whole plums and coarsely slice them. Spread the plums evenly over the tops of the cakes and gently press them into the batter. For this, I just use my finger.
Preheat the oven to 350°F and bake the cakes for 35-40 minutes, or until a skewer inserted in the center comes out clean. If using 20cm/8in tins, bake for a further 30-35 minutes, or until a skewer comes out clean.
Remove the cakes from the oven and cool for 10 minutes in their pans before putting out onto a wire rack to cool fully.

For the frosting:

In the bowl of a standing mixer fitted with a paddle attachment, place 200g/7oz butter. Gradually combine the icing sugar until it is completely incorporated. For about 5 minutes, beat until light and fluffy.
Mix in 4 tbsp of the blended roasted plum/juice combination until everything is well mixed.
If you’re preparing a four-layer cake, put 1 cup of frosting in a pastry bag with a star attachment and the rest in a pastry bag with a 1cm circle nozzle (or just snip the end off a ziplock bag).
Leave the frosting in the bowl if constructing a basic two-layer cake.

For a 4 layer cake:

Place the 15cm/6in cakes on a level surface. If there is a dome on the top of the cake, remove it with a knife and flatten the tops. Then, to produce four layers of cake, cut each cake in half horizontally.
On a plate or cake stand, place a layer of cake. Using the piping bag fitted with the simple round nozzle, pipe a ring around the outside of the cake. 2 tbsp frosting, spooned into the center of the layer and smoothed out to cover the layer 2 tblsp lime curd on top Repeat the same with the next layer of cake and the next layer after that. Finish with the last cake layer. To firm up the layers, place the cake in the refrigerator for 15-20 minutes.
The remaining frosting in the piping bag equipped with the round nozzle should be used to cover the cake.
To smooth the sides of the cake, run a pastry scraper or offset spatula soaked in hot water around them. To obtain the’semi-naked cake’ effect, uncover a little of the cake as you scrape.
Using the pastry scraper or spatula, smooth the top of the cake.
Pipe mounds of frosting on top using the piping bag with the star attachment.

For a simple 2 layer cake:

Place 1 x 20cm/8in cake on a plate or on a level surface. Spread 1/3 of the plum icing on top. 6 tablespoons lime curd
Place the second cake on top of the first.
2/3 of the plum icing should be on top.
To finish, drizzle more lime curd, freeze-dried plums, and/or edible flowers on top.

To serve:

Best consumed the same day, but will keep in an airtight container for up to 3 days. Cakes can be baked ahead of time, refrigerated in an airtight container, then frosted the next day.