1 chocolate cake mix
1 (8 oz.) pkg. cream cheese
1 egg
1/2 c. sugar
1/2 c. chocolate chips

Heat oven to 350 degrees. Grease and flour 15 x 10 x 1-inch pan. Prepare cake mix according to directions on package. Pour batter into pan. Mix remaining ingredients. Drop by tablespoons onto batter. Cut through batter with knife or spatula for marbled effect. Sprinkle with chocolate chips and nuts, if desired. Bake until cake springs back when touched lightly in center or when wooden pick inserted in center comes out clean, 25 to 30 minutes.