Preheat oven to 180°C / 160°C fan forced (356°F / or 320°F fan forced). Grease and line a loaf tin (22 cm x 11 cm x 7 cm high) with baking paper.
Add butter, caster sugar and vanilla to the bowl of an electric mixer. Beat for a couple of minutes until pale and creamy.
Add eggs one at a time and beat briefly for a maximum of 30-40 seconds.
Add sifted flour, baking powder, lemon zest, lemon juice and milk. Using a silicone spoon, gently mix the batter until wet and dry bits are fully incorporated and batter is just combined. Do not over mix.
Spoon batter into the prepared tin. Bake in the preheated oven for approximately 55-60 minutes until golden and cooked through the centre. Turn off the oven and let the cake sit in the warm oven for a further 3 minutes.
Remove and cool completely in the tin.
Prepare the icing by whisking icing sugar and yoghurt with a balloon whisk or electric beater until smooth and of pouring consistency.
Remove cake from the tin. Drizzle yoghurt icing over the cooled cake. Garnish with blueberries and lemon zest. Serve.
Cake will keep fresh in a cool corner of your kitchen for up to 2 days or in the fridge for up to a week.
Notes
Sugar - Raw caster sugar adds a lovely caramel tone and colour to the crumb. Turbinado or demerara sugar are great substitutes.
Vanilla extract - This is different from the liquid essence. It has a paste-like consistency and is very concentrated in flavour and aroma. Substitutions include the caviar from a whole vanilla pod or vanilla extract powder.
Eggs - If possible use organic, fresh eggs with an approximate weight of 60-65g per whole egg. Make sure eggs are room temperature.
Butter - You can use salted or unsalted butter. Soften it at room temperature before baking.
Milk - I use full cream milk. You can use light milk, soy milk, almond milk or any milk of choice.
Storage - The cake keeps fresh covered with a tea towel in a cool corner of your kitchen for up to 2 days or in an air-tight glass container in the fridge for up to a week.