*Crust*
1. In a bowl combine bread crumbs, sweetener and cardamom. With fingers,rub in margarine. Press onto bottom of 20 cm springform pan.
*Filling*
2. In a small dish or measure, sprinkle gelatin over quarter Cup of the grapefruit juice and let stand for 5 minutes to soften. Place dish of gelatin in pan of hot water and stir until gelatin dissolves completely. Cool to room temperature.
3. In food processor or blender, combine cottage cheese, banana, remaining juice. Puree until smooth.
4. Stir in dissolved gelatin and vanilla. Pour into crust.
5. Cover and chill in refrigerator for 2 to 4 hours or until set.
6. Remove sides from Pan and with wide metal lifter, slip cheesecake off bottom of pan onto serving plate, or leave on base of springform pan.
7. Peel grapefruit, removing all white pith. Separate segments and arrange on top of cheesecake. Slice strawberries and add to garnish if desired. Each serving is 0.125 of cheesecake.