Preheat your oven to 350oF (180oC). Butter and line an 8 x 8 inch tin with parchment paper and set aside.
Melt the butter in the microwave for 25-30 seconds or in a pot on the stovetop.
In a medium bowl whisk together the melted butter and brown sugar.
Make sure that the mixture isn't hot, then stir in the egg and vanilla.
Using a spatula, mix in the flour and salt. Once the batter is evenly combined fold in the white chocolate chips.
Transfer the batter into your lined tin, and bake for roughly 30 minutes, until the top is golden brown, and the middle is just set. To achieve the perfect blondie on the inside you want to make sure you bake then for just the right amount of time and don't over bake them.
Allow the blondies to completely cool in the tin before removing from the parchment paper and cutting.
Cut the blondies into 9 squares and enjoy warm preferably. Cover and store at room temperature for up to 3 days.