PREHEAT oven to 350° F. Grease or paper-line 16 muffin cups.
MICROWAVE 1/2 cup morsels in small, uncovered, microwave-safe bowl on HIGH (100%) power for 45 seconds; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10 to 15-second intervals, stirring just until morsels are melted. Cool to room temperature.
COMBINE flour, baking soda and salt in small bowl. Beat sugar, oil, egg and vanilla extract in large mixer bowl until blended. Beat in melted chocolate; gradually beat in flour mixture alternately with water (batter will be thin).
BEAT cream cheese, sugar, egg and salt in small mixer bowl until creamy. Stir in 1 cup morsels.
SPOON batter into prepared muffin cups, filling 1/2 full. Spoon filling by rounded tablespoon over batter. Spoon remaining batter over filling. Bake for 20 to 25 minutes or until wooden pick inserted in center comes out clean. While still hot, sprinkle with remaining 1/2 cup morsels. Let cool for 5 minutes or until morsels are shiny; spread to frost. Remove to wire racks to cool completely.