Preheat the oven to 180°C/350F/Gas Mark 4. Grease lightly and line your baking tin with some baking paper overlaping on two sides for easy blondie removal later.
Melt 150g of white chocolate and butter in bain-marie (heatproof bowl placed over a pan with simmering water). Make sure the bowl doesn't touch the water. Once melted remove from the heat.
Add brown sugar, eggs and vanilla extract and mix vigorously with a wooden spoon until combined.
Add flour, ground almonds, salt and almond flakes and mix well until incorporated.
Fold the raspberries in gently and spoon mixture onto prepared baking tin. If using fresh raspberries don't worry if some of them break during the process, it really is inevitable.
Bake in preheated oven for about 35 min or until toothpick inserted in the centre comes out clean but centre is still soft.
Let it cool before drizzling over some melted, white chocolate. When you're ready to drizzle, melt your remaining chocolate over baine-marie as above.
Cut into squares and serve with some more fresh raspberries if you like.