Cheesecake Swirl Brownies

1/2 c. butter or margarine
3 oz. unsweetened chocolate
1 c. sugar
2 eggs
1 tsp. vanilla
2/3 c. all-purpose flour
1/4 tsp. baking soda
1/2 c. chopped nuts
2 (3 oz.) pkgs. cream cheese, softened
1 egg

In medium saucepan melt butter and chocolate over low heat, stirring constantly. Remove from heat; cool. Stir sugar into chocolate mixture in saucepan. Add eggs, one at a time, beating by hand just until combined. Stir in vanilla. In small mixing bowl stir together flour and baking soda. Add flour mixture to chocolate mixture; stir just until combined. Stir in nuts if desired. In medium mixing bowl beat together cream cheese and egg. Spread 2/3 of brownie batter in greased 8-inch or 9-inch square baking pan. Drizzle cream cheese mixture on top. Drop remaining brownie batter by spoonfuls on top of cream cheese batter. Using a knife gently swirl to create a marbled effect. Bake in 350° oven 40 minutes for 8-inch pan, or 30 minutes for 9-inch pan. Cool on wire rack. Makes 16 bars.