• Preheat the oven to 200C/180C Fan/Gas 6. Line an 8 inch square baking tin.
• 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.
• 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. Fold in flour and chopped chocolate. Pour into tin, bake 27-30 minutes. Let cool on a wire rack.

For the Frosting

• Add the butter and vanilla to a large mixing bowl. Beat with a whisk on high for a minute to soften/combine everything.
• Add half the icing sugar, whisk on high. Then add the remaining half and whisk everything on high until fluffy. Add icing sugar/milk as required to meet your desired consistency. Spread over the cooled blondies, and optional: top with sprinkles!