Cut cake in half horizontally; separate layers. Place bottom cake layer, cut side up, on serving plate. Spread yogurt over cut surface. Place top cake layer on bottom layer, cut side down.
In medium bowl, beat whipping cream and powdered sugar with electric mixer on high speed until stiff peaks form. On low speed, beat in orange juice concentrate just until blended. Serve whipped cream with cake. If desired, garnish with orange peel curls. Store in refrigerator.