Preheat to 350°F (175°C) and line a 9×13-inch pan with parchment. Yes, parchment is your friend here.

Whisk melted butter with brown sugar until glossy. This is the foundation of flavor — don’t rush it.

Beat in eggs one at a time, then stir in vanilla. The batter should look lush and a little silky.

In a separate bowl, whisk flour, baking powder, and salt. Add dry mix to wet mix and stir just until combined.

Fold in white chocolate and macadamia nuts. Don’t overmix; you want pockets of gooeyness, not hockey puck batter.

Spread into the prepared pan in an even layer. A small offset spatula helps make it look pro.

Bake 25–30 minutes, until the edges are set and the center is just barely set. A toothpick should come out with a few crumbs. Don’t overbake unless you want brick blondies.

Cool completely in the pan before slicing into squares. Patience, my friend — it pays off with clean cuts.