1/2 cup unsalted butter, melted
1 cup white sugar
1 teaspoon vanilla extract
2 eggs, room temperature
1/2 cup all-purpose flour
1/3 cup unsweetened cocoa powder
1/4 teaspoon baking powder
1/4 teaspoon salt
2/3 cup toasted walnuts, chopped
Preheat oven to 350°F. Grease a 9×9 inch square, metal baking pan.
In a small bowl, whisk together flour, cocoa, baking powder, and salt. Set aside.
In a medium bowl, mix together the butter, sugar, and vanilla. Beat in eggs, one at a time.
Gradually stir flour into the egg mixture until well blended. Stir in walnuts. Spread the batter evenly into your prepared pan.
Bake for 25 minutes, or until they pull away from edges of pan. Let cool on a wire rack before cutting.