Preheat your oven to 180 degrees and line a 12 hole muffin tin with paper cases.
Place the butter into your Thermomix bowl and cook for 3 minutes at 60 degrees on speed 2 or until melted.
Add the self raising flour, caster sugar, milk, eggs and vanilla essence and mix for 10 seconds on speed 5. Scrape down. Mix for another 10 seconds on speed 5 or until just combined - it’s ok if the mixture is a little lumpy!
Add the blueberries and gently stir through using your spatula.
Spoon the mixture into the prepared muffin tin and bake for 18-20 minutes or until golden brown and cooked through when tested with a skewer.