Heat oven to 350 degrees. Grease square pan, 8x8x2 or 9x9x2. In large mixing bowl, blend melted butter, sugar and vanilla. Add eggs; using spoon, beat well. Combine flour, cocoa, baking powder and salt; gradually blend into egg mixture. Stir in chopped pecans. Spread in prepared pan. Bake 20 to 25 minutes or until brownies begin to pull away from sides of pan.
Meanwhile, prepare Chocolate Pecan Frosting. Spread warm frosting over warm brownies. Garnish with pecan halves. Cool completely, cut into squares. Makes 16 brownies.
CHOCOLATE PECAN FROSTING
1 1/3 cup confectioners sugar
3 tablespoons butter or margarine
2 tablespoons unsweetened cocoa
2 tablespoons milk
1/4 teaspoon vanilla extract
1/4 cup chopped pecans
In small mixing bowl place confectioners sugar; set aside. In small saucepan, melt butter; stir in cocoa, blend until smooth. Add milk; stir constantly over low heat until mixture is thickened. Pour hot mixture over confectioners sugar; beat until smooth. Stir in vanilla and pecans.