Heat the oven to 350 degrees.
Line a 10-by-15-inch pan with wax paper or aluminum foil, leaving an over-hang of about 1 inch at each end.
Butter and lightly flour the paper.
Stir the cocoa into the melted butter while it is still warm.
Fold in the remaining ingredients, one at a time, stirring until just combined.
Spread the batter in the prepared pan and bake for 25 to 30 minutes.
Using the overhanging paper as han-dles, lift the brownies out of the pan and cool on wire racks before cutting into squares.