Preheat your oven to 180C/160CFan, and grease & line a 9x9inch square tin and leave to the side.
Melt the unsalted butter carefully in the microwave, stir until smooth.
Using an electric whisk/stand mixer, whisk together the eggs & caster sugar for a few minutes until the colour has turned pale, is very mousse like, and is double the original volume of the amount of eggs + caster sugar! You will know it's done when you lift the whisk up out of the mix, it should leave a trail for a couple of seconds before disappearing!
Whilst whisking, beat in the melted unsalted butter a little at a time, making sure each bit of butter is fully combined before adding a bit more.
Sift in the plain flour, and fold the mixture together.
Add in the white chocolate chips and chopped pistachios, and fold again.
Pour the mixture into the tin, and bake in the oven for 30 minutes until there's just a slight wobble in the middle.
Leave the blondies to cool in the tin completely for at least 2 hours - they continue to cook once out the oven so don’t be afraid they are underbaked!
You can also leave them to ‘set’ in the fridge overnight!
Once cool/‘set’, drizzle over the melted white chocolate, and sprinkle on the extra chopped pistachios
Leave the chocolate to set, and then cut into your portions. (I did 4x4 to get 16 decent sized pieces!) Enjoy!
I use Callebaut Chocolate in ALL of my bakes other than when specified. I buy mine in 2.5kg bags as it makes it much easier and cheaper for me in the long run as I bake so much!