• 1 cup (2 sticks, 8 ounces) unsalted butter, melted
• 2 cups (15 oz) light brown sugar, firmly packed
• ¾ cup (2¼ oz) Dutch-process cocoa
• 1 tsp salt
• 1 tsp baking powder
• 1 tsp espresso powder (optional)
• 1 tbsp vanilla extract
• 4 large eggs
• 1½ cups (6¼ oz) King Arthur White Whole Wheat Flour (organic preferred)
• 2 cups (12 oz) semisweet or bittersweet chocolate chips
• ½ cup chopped walnuts (optional)

Special Equipment

• 9" x 13" baking pan
• microwave oven
• medium-sized microwave-safe bowl

1. Preheat the oven to 350°F and lightly grease a 9" x 13" pan
2. In a medium-sized microwave-safe bowl, or in a saucepan set over low heat, melt the butter, then add the sugar and stir to combine
3. Return the mixture to the heat (or microwave) briefly just until it’s hot (about 110°F to 120°F), but not bubbling. Don’t worry if it separates; just stir it briefly to recombine a bit. Heating this mixture a second time will dissolve more of the sugar, which will yield a shiny top crust on the brownies
4. Transfer the mixture to a bowl, and stir in the cocoa, salt, baking powder, espresso powder, and vanilla. Add the eggs,stirring till smooth; then add the flour and chips, again stirring till smooth. Spoon the batter into the prepared pan
5. Bake the brownies for 30 minutes, until a cake tester or sharp knife poked into the center reveals wet crumbs, but not raw batter. The brownies should feel set on the edges and in the center. Remove them from the oven, and cool completely on a rack
6. Cover and let sit overnight before cutting and serving; this gives the bran a chance to soften and become "invisible" in your mouth