Preheat oven: 180°C / 160°C (fan) / Gas Mark 4 / 350°F
Chop your strawberries into small pieces if not already, and set aside on a paper towel to absorb any excess liquid.
In a large heatproof bowl, melt the butter for 30-50secs in the microwave and beat in the sugars until smooth and thickened.
Thoroughly beat in the egg, vanilla extract and salt.
Sieve in the flour and cornstarch, stirring until just combined.
Gently fold in the white chocolate chips and strawberry pieces.
Pour the blondie mix into a greased and lined 8-inch square pan, smoothing the top gently.
Bake for 25-30mins until the top is lightly golden and there is only a slight wobble in the middle.
Allow blondies to cool fully in the tin before removing, then cut and enjoy!