In a small saucepan, combine the water, butter and chocolate. Cook and stir over low heat until melted; stir until smooth. Cool.
In a large mixing bowl, combine the flour, brown sugar, baking soda and salt. Add eggs,and sour cream; beat on low speed just until combined. Stir in chocolate mixture until smooth. In another mixing bowl, beat cream cheese, sugar, egg and vanilla; set aside.
Spread chocolate batter into a 15-in. x 10-in. x 1-in. baking pan coated with nonstick cooking spray. Drop the cream cheese mixture by tablespoonfuls over batter; cut through batter with a knife to swirl. Sprinkle with chocolate chips.
Bake at 375 degrees F for 20-25 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack.