Preheat your oven to 190°C | 370°F, (fan 170°C | 338°F) and grease a 12 cup muffin tin; you can use a little olive oil for this too, just spread it evenly around the tin.
Sieve 375g self-raising flour and 1/4 tsp baking powder into a large mixing bowl with 125g caster sugar.
Whisk together 225ml milk, 125ml olive oil, 2 eggs and 1-2tsp vanilla essence in a separate bowl or jug.
Mix your wet and dry ingredients and fold together until combined.
Add the zest and juice of 1 lemon and 200g blueberries and fold in carefully, but don’t over mix.
Evenly spoon the mixture into prepared muffin tins.
Bake on the middle shelf of the oven for 25-30 minutes, or until a skewer or knife comes out clean.
Leave to cool, then enjoy!