1. Line loaf pan with plastic wrap.
2. Cut cake into thirds lengthwise and place one slice cake into bottom of pan. Reserve remaining cake for future use.
3. Run knife along edge of frozen yogurt carton to loosen. Turn upside down and remove from carton.
4. Slice bottom third off and place over cake. Reserve ½ cup of yogurt and let soften.
5. Place pan in freezer for 30 minutes to harden.
6. Spread preserves over hardened frozen yogurt.
7. Combine the reserved cup of softened frozen yogurt with whipped topping and zest.Spread over preserve layer.
8. Freeze 8 hours or overnight to harden.
Tip: Garnish with fresh fruit.