Peanut Butter Chocolate Chip Brownies

For the potluck at work tomorrow. Stole the recipe from this message board.

Here's the recipe:

1/2 cup butter or margarine
1/2 cup smooth or crunchy peanut butter
1 cup brown sugar, packed
1 teaspoon vanilla
2 eggs
1 cup all-purpose flour
1 teaspoon baking powder
1/4 teaspoon salt
1 cup chocolate chips

Pre-heat oven to 350 degrees. Get out a 9" square baking pan.

Cream together butter and peanutbutter, gradually adding sugar and beating until fluffy. Blend in vanilla and eggs, one at a time, beating well after each addition. Mix flour, baking powder and salt together, then add to creamed mixture, mixing well. Fold in chocolate chips.

Spread in pan and bake approximately 30 minutes. Cool completely. If desired, sift some icing sugar over the brownies. Cut into 24 squares.

I've made these before and there's no way to get 24 squares out of a 9" pan. 16 squares, maybe. Normally, I try to substitute some of the butter for applesauce or one of the eggs for mashed banana and use whole wheat flour instead of all-purpose flour, but this time I said, screw it and stuck with the recipe. No point in getting my proportions/substitutions wrong and starting all over again.