Preheat your oven to 180℃.

Pour the melted butter, white sugar, and brown sugar into a medium sized mixing bowl. Stir to combine into a paste texture.

Crack the two whole eggs, one egg yolk, and vanilla paste into the bowl as well. Mix until incorporated.

In a separate large bowl whisk together the remaining dry ingredients - flour, cornflour, baking powder.

Fold the flour combination into the wet ingredients. Then mix in the white chocolate chips.

Spread the blondie batter into a square baking dish.

Place the blondie in the oven and bake for 25 minutes. Use a skewer at the end to ensure it is cooked, it should come out clean after poking the blondie.

You will want to let the blondies cool for about 15 minutes before serving, otherwise they will fall apart when you try to eat them - trust me from experience, sometimes it’s hard to be patient!