Pre-heat your oven to 200C/180C Fan/Gas Mark 6. Line an 8″ Square Pan with greaseproof paper.
In a small bowl, break up the white chocolate and melt in the microwave in 20 second intervals, stirring in between to make sure it doesn’t burn. Alternatively do this using a double boiler: Place the chocolate in a heat proof bowl resting on a small saucepan with simmering water. Stir until melted.
In a large mixing bowl, whisk together the melted butter and both sugars. Add in the eggs and vanilla extract and mix again.
Whisk in the melted white chocolate until fully incorporated. Add the flour and blueberries together and fold to combine.
Pour mixture into the pan. Sprinkle over the brown sugar to create a light layer. Bake 30 minutes.
Remove and let cool before slicing.
