Pre heat your oven to 180C / 350F / Gas Mark 4 and prep your baking tins with cupcake cases.

Cream the butter and sugar until light and fluffy.

Add the eggs one at a time mixing with an electric mixer in between each addition.

In a jug measure out your milk add the lemon juice and yogurt and mix.

In a separate bowl mix your flours.

Add a third of the flour to the egg mix and gently fold in. Then add a third of the milk mix in and fold in.

Keep doing this until everything is mixed in.

Get the lemon zest and blueberries and carefully fold into the cake batter.

Spoon the mixture into the cupcake cases. Try not to fill them more than 2/3rds full.

Pop them into the oven for 20-25 minutes, until they are a light golden colour and firm to the touch. Check as well with a toothpick that it comes out clean.

Leave then to fully cool.

Cream the butter until it is light and fluffy.

Add half the icing sugar and mix well, it may be a little stiff but this is to be expected at this stage.

Add the milk and lemon juice and stir it in.

Add the remaining icing sugar and once fully combined mix in the lemon zest.

Fill your piping bag with the buttercream and swirl it on top of your cupcakes.

Wash your blueberries and while they are still damp toss them in your tablespoon of caster sugar to give them a crystallised look.

Place three of them on each cupcake and serve.