Brownies With Chocolate-Covered Raisins

1½ cups (3 sticks) unsalted butter, cut into pieces 12 ounces semisweet chocolate, chopped  2 ounces unsweetened chocolate, chopped  1½ cups sugar  4 large eggs  2 teaspoon vanilla extract  1⅓ cups all-purpose flour  1½ teaspoons baking powder  ½ teaspoon salt  2 cups chocolate-covered raisins

Calories 247 (52% from fat) • carb. 29g • pro. 3g • fat 15g • sat. fat 9g • chol. 50mg • sod. 62mg • calc. 21mg • fiber 2g

1. Preheat oven to 350°F. Butter 13 x 9 x 2 - inch rectangular pan. Combine the butter and both chocolates in a 2¾ quart Cuisinart® saucepan. Cook over low heat until completely melted. Remove from heat; cool to lukewarm. 
2. Using the Cuisinart® SmartPower Hand Mixer, beat sugar and eggs in medium bowl until very thick and pale using medium speed, about 3 minutes. Stir in melted chocolate mixture and vanilla. 
3. Mix flour, baking powder and salt in another medium bowl. Stir into chocolate mixture using low speed. Mix in chocolate-covered raisins. Pour batter into prepared pan. Bake in preheated 350F oven until tester inserted into center comes out with a few moist crumbs attached and top cracks in places, about 30 minutes. Transfer to rack and cool in pan. 
4. (Can be made 1 day ahead. Cover with foil and let stand at room temperature.) Cut into squares to serve.