Preheat oven to 350. Grease and flour one 9 inch square baking pan, tapping out excess flour.
Melt the butter and unsweetened chocolate in the top of a double boiler and then let cool for about 15 minutes.
Sift together both flours, baking powder and salt. Set aside. In Large bowl, whisk chocolate/butter mixture to blend. Beat in sugar, then vanilla, then eggs. Fold in dry ingredients and mix well. Stir in semisweet chocolate chips. Scrape batter into prepared pan, spreading evenly.
Bake at 350 degrees F (175 degrees C) for 30 to 35 minutes until set. Do not overbake. Cool in pan on a wire rack. Once cool cut into large squares.