Double Chocolate Walnut Brownies

1 cup butter

4 (1 ounce) squares unsweetened chocolate

2 cups white sugar

3 eggs

1 teaspoon vanilla extract

1 cup all-purpose flour

1 ½ cups chopped walnuts

1 cup semisweet chocolate chips

Melt butter and 4 squares unsweetened chocolate in a medium size saucepan over moderate heat. Remove from heat.

Preheat oven to 350 degrees F (175 degrees C).

Beat in sugar gradually with a wooden spoon until thoroughly combined. Add eggs, one at a time, beating well after each addition; stir in vanilla. Stir in flour until thoroughly combined. Stir 1 cup of the walnuts.

Spread into greased 13 x 9 x 2 inch pan. Combine remaining 1/2 cup walnuts with chocolate chips; sprinkle over top of brownie mixture, pressing down lightly. Bake in a preheated oven for 35 minutes or until top springs back when lightly pressed with fingertip. Cool completely in pan on wire rack. Cut into bars or squares.