Preheat oven to 350. Toast coconut on rimmed baking sheet, stirring 2 to 3 times, until light golden, about 5 to 7 minutes.
Whisk flour, baking powder and salt together in a medium bowl; set aside.
Whisk melted butter and brown sugar together in medium bowl until combined. Add eggs and vanilla and mix well. Using rubber spatula, fold dry ingredients into egg mixture until just combined; do not overmix. Fold in chocolate, coconut and nuts and turn batter into 13x9-inch baking pan coated with cooking spray. Smooth top with rubber spatula.
Bake until top is shiny, cracked and light golden brown, 22 to 25 minutes; do not overbake. Cool on wore rack to room temperature. Cut into 2-inch squares and serve.
Bake
2005, 2010