In a small bowl, combine the crushed cones, walnuts and butter; press onto the bottom of a greased 9-in. springform pan.
In another small bowl, combine 3 cups yogurt, bananas and extract if desired. Spread over crust. In a small bowl, combine fudge topping and walnuts; spread over yogurt. Cover and freeze for 2 hours or until firm.
Top with remaining yogurt; spread with strawberry topping. Cover and freeze for 8 hours or overnight until firm. Garnish with whipped topping. Yield: 12 servings.