Preheat the oven to 200°C, fan 180°C, gas 6.
Line a 12-hole muffin tin with paper or silicone cases.
Add the butter, sugar, eggs, vanilla extract, lemon zest, flour and a pinch of salt to a mixing bowl and whisk with an electric whisk until you have a lovely smooth batter.
Stir through the blueberries, then divide between the cases.
Bake for 15-20 minutes or until golden and risen.
Transfer to a wire rack to cool, then dust with icing sugar to serve.
