This light and fluffy blueberry lemon cake is a cinch. Just make sure all your ingredients are at slightly warmer than room temperature to help it blend easily. If you don’t 15cm (6-inch) baking tins, you can use two 20cm (8-inch) deep sandwich tins instead, you won’t have the majestic height but it will taste just as delicious. Russian buttercream uses condensed milk for a super light and lovely finish and no messy clouds of icing sugar.
Method:

• Heat the oven to 170°c and grease (or cake spray) and line the base of your baking tins with baking parchment.
• Divide the buttermilk equally into two bowls. Add the oil to one bowl and the eggs, lemon zest and juice and lemon extract if using to the other. Whisk the egg mixture lightly to break up the eggs.
• Next place the flour, sugar, baking powder, bicarbonate of soda and salt in the bowl of a stand mixer with the paddle attachment and add the butter in small chunks, piece by piece, until the mixture resembles coarse sand.
• Tip in the buttermilk/oil mix and beat on medium speed for two minutes. Slow the mixer to low and then add the egg mixture in thirds, allowing each third to incorporate fully before adding the next.
• Once it is all mixed, divide the batter between your cake tins and give them a sharp tap on the work surface to level and remove any air pockets.
• If using FRESH blueberries wash them and then dust with a tablespoon or two of plain flour and then scatter evenly over the top of the cakes. You do not need to mix them in as this will encourage them to sink to the bottom. If using FROZEN blueberries, you can skip the flour and just put the frozen berries on top of the batter.
• Bake in the centre of the oven for 30-40 minutes until well risen and a toothpick comes out clean when inserted in the middle of the cakes,
• Allow to cool in the tins on a rack until warm and then turn out onto the rack until room temperature.
• To make the Russian buttercream: beat 225g unsalted butter for at least eight minutes on high speed, you want the butter to be extremely light and fluffy. Scrape down the sides at regular intervals so there are no yellow streaks. Next add the condensed milk gradually ensuring to scrape down the bowl all the way to the bottom. Keep beating until you have a stiff yet pliable buttercream. Add the salt and the lemon/vanilla extract and beat to incorporate.
• If it looks like it is splitting put it in the fridge for 5-10 minutes and beat again on high speed.
• Sandwich the cakes together with 1/3rd of the icing then smooth the rest of the icing over the cake with a spatula. You can choose if you’d rather ice it all over of keep to a more naked cake look using it only in between the layers. (see photo below)
• Decorate with blueberries and lemon slices.
• Photo Inbal Bar-Oz[Missing Credit]