Melt your unsalted butter in the small saucepan slowly. Let it turn golden brown until it smells nutty. Pour it into a bowl to cool down slightly.

Add the brown sugar to the warm brown butter. Whisk them together until the mixture is very smooth. This creates the base for your chewy blondie bars.

Crack your eggs into the buttery sugar mixture now. Add the vanilla extract and whisk until very light. This adds air and moisture to the sweet batter.

Sift the flour, baking powder, and salt together today. Fold the dry ingredients into the wet batter gently. Do not overmix the batter to keep it soft.

Stir in the white chocolate chips with a spatula. Pour the thick batter into your lined baking pan. Spread it out to the corners very evenly now.

Bake in a preheated oven until the edges are firm. The center should still be a little bit soft. Let them cool fully before you cut into squares.