Pre-heat the oven to 150° C. Grease and line an 8” round baking tin with parchment paper.
Melt the butter in a saucepan over gentle heat.
Turn the heat off; add the sugar and stir until well combined.
Grate in the zest of a small lemon and stir well.
Next add the juice of the lemon. This should be roughly 4 tsps of lemon juice1.
Add a third of a cup of thick yogurt and tbs of milk to the mix; stir well again.
Sift in the flour and the baking powder. Mix vigorously with a wooden / silicone spatula until well combined2.
Beat eggs until fairly frothy like you see in the image below; gently fold them into the batter.
Next, fold half the quantity blueberries into the batter.
Pour the batter into a baking tin and use a spatula to ensure its evenly spread. Tap the pan gently on the surface of your kitchen counter / table to release any air bubbles.
Top the cake with the remaining blueberries. Place them randomly or in a pattern; just make sure they are evenly distributed.
Place the cake tin in a pre-heated oven and bake for 45 – 50 mins, or until a skewer/toothpick when poked into the middle comes out clean. When done, the cake should be golden around the edges, and the blueberries should have begun to ooze a deep, purple syrup. Run a knife around the edges of the cake tin, so that it releases easily once cooled.
This next step is completely optional3, and you can do without it unless you want an extra lemony-hit! Pierce the top of the cake with a skewer/ tooth pick all over (not too deep), while its still warm. Mix together a tsp of lemon juice with a tsp of caster sugar and spread this over the top of the cake. Allow to cool for another 20 - 25 minutes before removing from the tin.
Once the cake has cooled completely, remove from the tin and serve! (Preferably with a hot cup of tea)