BRING butter, sugar, salt and water to boil in saucepan. Add flour; stir vigorously with wooden spoon on medium heat until mixture pulls away from side of pan. Transfer to mixer bowl fitted with paddle attachment. Beat on low speed 1 min.
ADD whole eggs, 1 at a time, beating on medium speed until well blended. Mix in egg whites. Add food coloring and cocoa powder; mix until well blended. Spoon batter into pastry bag fitted with a large round tip.
SPRAY parchment paper-lined sheet pan with cooking spray. Pipe 4-inch-long éclairs (about 3 oz. each) onto paper. Bake in 425ºF standard oven 10 min. Reduce heat to 350ºF. Bake 20 min. or until the exterior is firm and dry. Cool completely before filling.
MELT chocolate in double boiler. Spoon Cheesecake Batter into pastry bag fitted with small round tip. Pierce the end of each éclair shell and fill with 1 Tbsp. Cheesecake Batter. Dip tops into chocolate then sprinkle with nonpareils.