Raspberry brownies

1 cup (2 sticks) butter or margarine
5 ounces unsweetened chocolate, chopped
2 cups sugar
4 large eggs
2 teaspoons vanilla
1-1/4 cup all-purpose flour
1 teaspoon baking powder
1/2 teaspoon salt
1 cup chopped walnuts
1/2 cup Smucker`s Red Raspberry Preserves

1. Butter 13 x 9 x 2-inch baking pan. Melt butter and chocolate in a large, heavy saucepan over low heat, stirring constantly until smooth. Remove from heat. Stir in sugar, eggs, and vanilla. Mix flour, baking powder and salt in small bowl. Add to chocolate mixture and whisk to blend. Stir in nuts.
2. Pour two cups batter into pan. Freeze until firm, about 10 minutes.
3. Preheat oven to 350 F. Spread preserves over brownie batter in pan. Spoon remaining batter over. Let stand 20 minutes at room temperature to thaw bottom layer.
4. Bake brownies until tester inserted into center comes out clean, or about 35 minutes. Transfer to rack and cool. Cut brownies into squares. Store in airtight container at room temperature.