1/2 cup butter or margarine
4 ounces unsweetened baking chocolate -- chopped
1 1/3 cups sugar
3 large eggs
1 1/2 teaspoons vanilla extract
3/4 cup all-purpose flour
Heat oven to 350 degrees. Line an 8 inch square baking pan with foil, letting ends extend above pan on 2 sides. Coat foil with nonstick spray. Melt butter and chocolate in a medium saucepan over low heat, stirring often. Remove from heat. Whisk in sugar, then remaining ingredients until smooth. Spread batter in pan. Bake25-30 minutes until a wooden pick inserted in center comes out with moist crumbs attached. Cool in pan on wire rack. Lift foil by ends onto cutting board. Cut into 16 squares.