Directions

1. Position an oven rack in the center of the oven and preheat the oven to 350ºF/180ºC/gas 4. Generously coat 2 brownie bar or financier pans with baking spray. Set aside.
2. In a small saucepan over medium-low heat, melt the butter. Remove from the heat. Split the vanilla bean lengthwise and scrape out the seeds with the back of a knife. Add the seeds and pod to the melted butter and place back on the heat. Cook, swirling the pan frequently, until the butter darkens to a nutty brown and the solids drop to the bottom of the pan, 8 to 12 minutes. Remove from the heat and discard the vanilla bean pod. Add the orange zest to the browned butter and set aside.
3. In a medium bowl, whisk the egg whites until loosened and barely foamy. Set aside.