Chocolate Brownie Bread

4 (1 ounce) squares unsweetened baking chocolate
1/2 cup (1 stick) butter or margarine
1 cup granulated sugar
1 cup firmly packed brown sugar
2 eggs
1 cup sour cream
1 teaspoon vanilla extract
1 1/2 cups flour
2 teaspoons baking powder
1/4 teaspoon baking soda
1 cup finely chopped toasted walnuts or pecans

Heat oven to 350 degrees F. Grease and flour 9 x 5-inch loaf pan.

Microwave chocolate and butter in large microwaveable bowl on HIGH 2 minutes or until butter is melted. Stir until chocolate is completely melted. Add sugars; mix well. Blend in eggs, sour cream and vanilla. Add flour, baking powder and baking soda; mix well. Stir in walnuts. Spread into prepared pan.

Bake 1 hour to 1 hour 10 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes; remove from pan to wire rack. Cool completely.

Cut into 16 slices to serve.