Preheat your oven to 180°C (160°C Fan, Gas Mark 4). Grease and line a 23x23 cm square baking tin with baking parchment. This will help you remove the Blondies easily after baking.

In a large mixing bowl, melt the butter until smooth but not hot. Add the brown sugar and whisk together until well combined and glossy. Crack in the eggs one at a time, whisking well after each addition. Stir in the vanilla extract.

Sift in the flour, baking powder, and salt. Fold the dry ingredients into the wet mixture using a spatula or wooden spoon until just combined – avoid overmixing to keep the Blondies soft and chewy.

Fold in the chopped white chocolate chunks evenly through the batter. 

Pour the batter into the prepared tin and smooth the top with a spatula. Tap the tin lightly on the worktop to release any large air bubbles. Bake in the preheated oven for 25-30 minutes, or until set and the top is golden with a light crackle. Turn off the oven and leave the door slightly ajar and leave to cool in the oven for 15 minutes. Take out the oven and allow to cool to room temperature, before popping in the fridge to set completely 

Once cooled, lift out using the parchment, slice into squares, and serve. Enjoy your delicious homemade Blondies as a sweet snack or dessert!