Heat oven to 350°F.

Grease 8-inch square baking pan.

Combine butter, sugar and vanilla in bowl.

Add eggs; beat well with spoon.

Combine flour, cocoa, baking powder and salt; gradually add to egg mixture, beating until well blended.

Spread batter evenly into prepared pan.

Bake 40 to 45 minutes or until brownies begin to pull away from sides of pan.

Cool completely in pan on wire rack.

Cut into bars