Heat oven to 350°F. Grease and flour 9x9x2" pan. Melt butter in
2 qt saucepan; remove from heat. Mix in cocoa, sugar, and eggs.
Stir in remaining ingredients except topping. Spread in pan. Bake
for 23 minutes.
Meanwhile, prepare topping:
Melt butter in 1 qt saucepan; remove from heat. Mix in sugar, eggs,
and egg yolk. Stir in remaining ingredients. Immediately pour
topping over brownies; spread evenly. Bake about 18 minutes longer
or until firm; cool.