PREHEAT oven to 350°F. Grease and flour 9-inch springform pan. Mix cold water, corn syrup, sugar and cornstarch in large heavy saucepan. Cook on low heat until sugar is dissolved, stirring constantly with wire whisk. Add chocolate and salt; increase heat to medium. Continue cooking until chocolate is completely melted and mixture just comes to boil, stirring constantly. Remove from heat. Add butter; stir until melted. Transfer mixture to large bowl. Refrigerate 15 min. or until cooled, stirring occasionally. (Mixture can still be slightly warm to the touch.) Add eggs; mix well.

BEAT whipping cream in small bowl with electric mixer on high speed until soft peaks form. Add to chocolate mixture; stir gently until well blended. Spoon into prepared pan. Place pan in larger shallow baking pan, then place on center rack in oven. Carefully pour boiling water into larger pan to come halfway up side of springform pan.

BAKE 45 min. or until center is set. (Top will feel slightly firm to the touch.) Remove springform pan to wire rack. Run knife or metal spatula around rim of pan to loosen cake; cool before removing rim of pan. Cover top with plastic wrap. Refrigerate 4 hours or overnight. Garnish with chocolate curls, if desired. (See Tip.) Store leftover cake in refrigerator.