1 cup Nutella
1/4 cup plus 2 tablespoons water
1 (16 ounce) frozen pound cake, defrosted
1 envelope gelatin
1 cup heavy cream
1 cup non-fat sour cream
2 cups mixed fresh berries such as strawberries, blackberries and blueberries, sliced
Nonstick cooking spray
Spray inside of 9-inch round springform cake pan with nonstick cooking spray and line sides with aluminum foil or plastic wrap.
In medium bowl, whisk together Nutella and 1/4 cup water until smooth, creating rich Nutella syrup. Set aside.
Cut 15 width-wise slices (1/2-inch each) of pound cake with serrated knife and use 10 slices to line pan's inside edge, pressing sides to form overlapping pattern. Place remaining 5 slices on bottom to fill pan's base, cutting pieces as necessary to fill holes. Drizzle cake bottom with 1/4 cup Nutella mixture.
In large bowl, whip heavy cream until soft peaks form. Add sour cream and 1/2 cup Nutella mixture and continue to beat until mixture once again holds soft peaks.
Meanwhile, in small microwavable dish, place 2 tablespoons water and sprinkle with gelatin. Let stand for 1 minute. Microwave on HIGH for 20 to 30 seconds to soften gelatin. Stir until gelatin completely melts.
Whisk melted gelatin into Nutella-cream mixture until completely blended to create mousse-like texture.
Layer bottom of cake with 1 cup mixed berries. Spread mousse over berries. Remove cake from pan and place on serving dish. Drizzle with remaining Nutella syrup. Make decorative pattern on cake with remaining 1 cup berries. Refrigerate for 1 hour before serving.
Serving ideas: Using remaining 1 cup of berries, lay strawberries in concentric-circle pattern with pointed end of each strawberry facing outward. Fill center with remaining berries. Dust with confectioners sugar just before serving.