Preheat oven to 350 degrees F.
1. Melt butter.
2. Stir in sugar and vanilla.
3. Add eggs, one at a time, beating well after each.
4. Add cocoa, beat until well blended.
5. Add flour, baking powder, and salt. Beat well.
6. Pour into buttered and floured 9x13 pan.
7. Bake for 30-35 minutes or until brownies pull away from the sides of the pan.