Ingredients:

¾ cup all-purpose flour

½ teaspoon baking powder

¼ teaspoon salt

3 tablespoons unsalted butter

½ cup unsweetened cocoa powder

2 teaspoons vanilla extract

¾ cup granulated sugar

¼ cup packed brown sugar

1 large egg

2 large egg whites

¾ cup, divided chopped walnuts

Directions:

Step 1

Preheat the oven to 350°F. Line an 8-inch square baking pan with foil or parchment, allowing the foil or parchment to extend over the rim of the pan by 2 inches. Spray with cooking spray.

Step 2

In a small bowl, whisk together the flour, baking powder and salt. Set aside.

Step 3

In a medium saucepan, melt the butter over low heat. Remove from heat and whisk in the cocoa powder and vanilla extract. Let stand 5 minutes.

Step 4

Add the granulated sugar, brown sugar, egg and egg whites to the cocoa mixture. Whisk until blended. Stir in the flour mixture until blended. Stir in 1/2 cup of walnuts.

Step 5

Scrape the batter into the baking pan and spread evenly. Scatter the remaining 1/4 cup of walnuts over the batter. Bake until a toothpick inserted into the center comes out with moist crumbs clinging, 20–25 minutes.

Step 6

Let cool completely in the pan on a rack. Lift from the pan using the overhanging foil or parchment as handles. Cut into 16 squares. Note: For easier cutting, refrigerate the cooled brownies about 1 hour.