01 -
Preheat oven to 175°C. Line a 20 x 20 cm pan with foil or parchment and spray lightly with nonstick spray.
02 -
Combine chocolate chips, sweetened condensed milk, and butter in a small saucepan over low heat. Stir frequently until fully melted and smooth, then set aside to cool slightly.
03 -
In a large bowl, mix the melted butter and brown sugar until blended. Stir in the egg and vanilla extract until smooth. Add fine salt and flour, folding just until combined to form a thick batter.
04 -
Spread half of the blondie batter evenly in the prepared pan. Flatten cooled fudge filling with your hands and arrange pieces over the batter to cover. Gently spread the remaining blondie batter on top to conceal the filling.
05 -
Bake for 25 minutes, or until the top is lightly golden and the center remains moist. Allow to cool completely before slicing and serving.