Raspberry Brownies

1/2 cup butter, softened
1 cup granulated sugar
2 large eggs
2 (1 ounce) squares unsweetened chocolate, melted
3/4 cup all-purpose flour
1 cup chopped walnuts
1/3 cup raspberry jam

Beat butter until soft and creamy. Gradually add sugar, beating well. add eggs and chocolate, mixing well. Add flour to butter mixture, mixing well. stir in walnuts. Spoon half of batter into a greased and floured 9-inch square pan. Spread raspberry jam over batter; top with remaining batter. Bake at 350 degrees F for 28 to 30 minutes.