Preheat the oven to 180C/ 160C F/Gas 4. Line the base and sides of a 20cm square cake tin with baking paper, leaving enough paper overhanging to help lift the cooked blondie out of the tin.
Brown the butter by putting it in a pan set over a medium heat. Cook the butter, swirling the pan occasionally, until the butter has melted and starts to bubble rapidly. Once the bubbles slow and the butter starts to foam, watch carefully. When small brown flecks appear at the bottom of the pan, quickly remove from the heat and set the butter aside to cool slightly.
When the browned butter has cooled to warm, put the caster sugar, brown sugar, vanilla and eggs in a large mixing bowl and use a hand whisk to mix well. Whisk in the warm browned butter.
Put the flour, salt and malted milk powder In a separate bowl, mixing to combine. Fold the dry ingredients, along with half the chopped white chocolate, into the egg and sugar mixture. Pour the batter into the prepared tin, smoothing the top with a spatula. Gently dot the top of the blondie with the remaining white chocolate, spoonfuls of the chocolate hazelnut spread, and the hazelnuts.
Sprinkle the surface with sea salt flakes and bake for 25-35 minutes or until the surface of the blondie is set, but it is still a little wobbly in the middle.
It will continue to cook as it cools and you want it to be a little soft inside.
Allow to cool completely in the tin before carefully liftingthe blondie out and slicing to serve. It will keep in an airtight container in a cool place for up to a week.
RECIPES AND PHOTOGRAPHS TAKEN FROM HANDFULS OF SUNSHINE BY TILLY PAMMENT, PHOTOGRAPHY BY MATILDA PAMMENT (MURDOCH BOOKS, £22)
