In a large mixing bowl, combine the lemon zest and sugar and rub the two together with your fingers to flavour the sugar. Add the eggs and whisk until pale, smooth and frothy.
In the same bowl, combine the lemon juice, olive oil, Greek yoghurt and vanilla essence and whisk until all ingredients are well combined. Sift in the flour and baking powder and gently combine the wet and dry ingredients. Add 1 punnet of blueberries and gently fold through with a spatula.
Drizzle a 24 x 10cm loaf tin with olive oil and brush all over the sides and bottom. Transfer the cake batter to the loaf tin and smooth out on top with a spatula. Scatter the remaining blueberries on top and push them into the batter so their tops are slightly exposed.
Bake for 55 minutes or until golden on top and a skewer comes out clean when poked into the middle. Leave to cool for 15 minutes in the tin then transfer to a cooling rack. Drizzle with the lemon drizzle and serve on its own or with ice cream.
Lemon drizzle
Mix your icing sugar and lemon juice together until you have a smooth and pouring consistency. You can always add more lemon juice if your drizzle is too thick or more icing sugar if it is too thin.