PREHEAT oven to 375°F. Beat eggs, sugar, flour, milk and vanilla in small bowl with electric blender on medium speed 30 sec. or until well blended.
SPREAD cherries evenly onto bottom of greased 9-inch pie plate; cover with batter. Sprinkle evenly with chocolate.
BAKE 40 to 45 min. or until top is puffed and golden brown and center is just set. Cool 10 min. Top with the whipped topping just before serving.