PREHEAT oven to 350° F.
COMBINE cocoa, flour and salt in small bowl. Beat eggs and 1 teaspoon vanilla extract in small mixer bowl; blend in sugar and butter. Add cocoa mixture; blend well. Stir in 3/4 cup morsels. Place crust on baking sheet; pour batter into crust.
BAKE for 45 minutes or until set. Cool on wire rack.
COMBINE remaining morsels, cream and remaining vanilla extract in small, uncovered, microwave-safe bowl. Microwave on MEDIUM-HIGH (70%) power for 1 1/2 minutes; STIR. If necessary, microwave at additional 10- to 15-second intervals, stirring just until melted. Cut pie into wedges; top with ice cream. Spoon sauce over ice cream.