The Cake Slice July 09: Marbled Lemon Blueberry Butter Cake

What a great choice this months Cake Slice was. Lemon and blueberries are a great flavour combination and this cake combines the two. It involves making a fresh blueberry preserve to sandwich together a light lemony cake. Some of the blueberry preserve is also swirled through the batter to create a mottled marble surface to the cake layers. The whole cake is then topped off with a creamy lemon buttercream.
I really enjoyed making my own blueberry preserve for this cake, rather than relying on a jar. Quite a thin spreading is used to sandwich the cakes together and as it’s the only filling I initially thought it looked a little stingy but the depth and intensity of the blueberry flavour really shone through and it was more than sufficient. I loved its deep purple colour too, a perfect contrast to the pale creamy cake layers and frosting.

The cake itself was very light and tender. The cake was made using only egg whites and the resulting layers rose well and had a good structure. I often have trouble with egg white only cakes, they tend to shrink on me, but this one turned out perfectly. The lemon flavour was very subtle, I think next time I will add more lemon zest as I like my lemon quite zingy.

The frosting was another success. It is an egg enriched buttercream, but unlike the buttercreams I have made in the past, this one was made using whole eggs rather than just the egg white. The results were amazing! It turned out so silky smooth and creamy and it melted on your tongue like… well like butter and it was not grainy in the slightest. My dad announced this was the best frosting he’s ever tasted so it’s definitely one I will be using again in future. It whipped up to be beautifully thick and the perfect spreadable consistency. At room temperature it was soft and creamy and after a night in the fridge it firms up, but both consistencies are wonderful. Needless to say, this cake didn’t last long in my house. Click to see the other Cake Slice cake bakers.

Marbled Lemon Blueberry Butter Cake
(Recipe from Shy High Irresistible Triple Layer Cakes by Alisa Huntsman & Peter Wynne)
Lemon Cake Layers
200g unsalted butter, at room temperature
250g caster sugar
2 tsp grated lemon zest
1½ tsp lemon extract
7 egg whites
360g American cake flour OR 280g plain flour & 80g cornflour
4 tsp baking powder
½ tsp salt
280ml milk
Fresh blueberries, for decoration

Lemon blueberry preserves (below)
Lemon buttercream frosting (below)

Preheat the oven to 180C. Butter the bottom and sides of three 8 inch round cake pans. Line the bottom of each pan with a round of parchment or waxed paper and butter the paper.
In a mixer, cream together the butter, sugar, lemon zest and lemon extract until light and fluffy. Gradually add the egg whites 2 or 3 at a time, beating well between additions and stopping occasionally to scrape down the sides of the bowl.
Combine the flour, baking powder and salt, whisk gently to blend. In 2 or 3 alternating additions, beat the dry ingredients and milk into the butter mixture, scraping down the sides of the bowl several times. Beat on medium-high speed for about 1 minute to smooth out any lumps and aerate the batter.
Scoop 4 tbsp of the batter into a small bowl. Divide the remaining equally among the 3 prepared pans, smoothing the tops with a spatula. This gives you a smooth surface to work with. Add 2½ tbsp of the lemon blueberry preserves to the reserved batter and blend well. Drizzle heaping teaspoons of this blueberry mixture over the batter in the pans. Use a skewer to swirl the blueberry mixture in short strokes to drag it down through the lemon batter without mixing it in.
Bake for about 25 minutes or until a cake tester or skewer stuck in the centre comes out clean and the cake pulls away from the sides of the pan. Lat the layers cool for 10 minutes before turning out onto a wire rack, peeling off the paper and leaving to cool completely.

Lemon Blueberry Preserves
375g blueberries, fresh or frozen
165g caster sugar
2 tbsp freshly squeezed lemon juice
1½ tsp grated lemon zest
1 tsp grated fresh ginger

Puree the blueberries with any juices that have exuded in a blender. Pass the puree through a coarse strainer to remove the skins.
In a heavy medium saucepan, combine the blueberry puree with the sugar, lemon juice, zest and ginger. Bring to a gentle boil over a medium heat, stirring often for 20 minutes, or until the preserves have thickened and are reduced by half. To check the proper thickness place a small amount of a saucer and put in the freezer until cold. Drag your finger through it. If a clear path is made through the preserve then it is ready. Let the preserves cool before using. (Can be made up to 5 days in advance).

Lemon Buttercream Frosting
225g caster sugar
55ml water
2 eggs
300g unsalted butter, at room temperature
2 tbsp freshly squeezed lemon juice

In a small saucepan, combine the sugar and water. Bring to the boil over a medium heat, stirring to dissolve the sugar. Continue to boil without stirring, occasionally washing down the sides of the pan with a wet pastry brush until the syrup reaches the soft-ball stage, around 115C on a sugar thermometer. Immediately remove from the heat.
In a large mixer bowl with an electric mixer on medium speed, beast the eggs briefly. Slowly add the hot syrup in a thin stream, pouring it down the sides of the bowl; be careful to avoid hitting the beaters or the syrup may splatter. When all the syrup has been added, raise the speed to medium,-high and beat until the mixture is very fluffy and cooled to body temperature. This can take 15-20 minutes.
Reduce the mixer speed to medium-low and gradually add the softened butter 2 to 3 tablespoons at a time, beating well between additions. As you’re adding the last few tablespoons of butter, the frosting will appear to break, then suddenly come together like whipped butter. Beat in the lemon juice, and the frosting is ready to use.
To Assemble
To assemble the cake, place a layer, flat side up, on a cake stand. Spread half of the lemon blueberry preserves over the top. Place a second layer on top of the first and spread the remaining preserves over it. Finally place the third layer on top and frost the top and sides with the lemon buttercream.
Decorate with fresh blueberries and serve.
Makes one 8 inch triple layered cake