Line 8x4-inch loaf pan with plastic wrap. Microwave first 4 ingredients in medium microwaveable bowl on HIGH 2-1/2 min. or until chocolates and butter are completely melted and mixture is well blended, stirring after 1-1/2 min. Cool completely. Stir in vanilla. Refrigerate 30 min. or until thickened.
Spoon 1/2 cup COOL WHIP into small bowl. Refrigerate for later use. Gradually add remaining COOL WHIP to chocolate mixture, stirring constantly until well blended. Spoon into prepared pan.
Refrigerate 3 hours. Unmold dessert onto plate; remove plastic wrap. Top dessert with reserved COOL WHIP.
Cut dessert into slices; top with strawberry pure and whole strawberries.
