In small bowl, combine flour, baking soda and salt. In small saucepan, melt butter and sugar with water; stir until sugar is dissolved. Add 2 cups chocolate chips; stir until melted. Remove from heat. Stir in vanilla; cool slightly. In large bowl, beat eggs with electric mixer. Add melted chocolate; mix well. Add flour mixture; stir until just combined. Spread batter in prepared pan.