1 cup butter or margarine, melted and cooled
2 cups sugar
2 teaspoons vanilla
4 eggs
3/4 cup cocoa
1 cup flour
1/2 teaspoon baking powder
1/4 teaspoon salt
1 cup chopped walnuts or pecans (optional)
Preheat oven to 350 degrees. Grease a 9x13 inch pan. In large bowl, stir in melted butter, sugar, and vanilla. Add eggs, one at a time, beating well with spoon after each addition. Add cocoa; beat until well blended. Add flour, baking powder, and salt; beat well. Stir in nuts if desired. Pour batter into prepared pan. Bake 30 -35 minutes, or until brownies begin to pull away from sides of pan. Cool completely and cut into bars.