Preheat your oven to 180 degrees Celsius or gas mark 4.
In a large pan, gently heat the butter. white granulated sugar and light brown sugar until the butter melts and forms a smooth mixture.
Add the eggs and almond extract and beat until combined.
Fold in the gluten free plain flour, cornflour and ground almonds until smooth, then add the white chocolate chips and stir well.
Pour the blondie mixture into a square, 20 x 20 cm lined tin. Randomly spoon the jam on top and swirl gently.
Sprinkle the top with flaked almonds and bake for 25-30 minutes.
Leave to cool before slicing into individual blondies.