In bowl combine gelatin and enough milk to moisten. Set aside. In saucepan combine whipping cream and sugar. Cook and stir over medium heat until sugar is completely dissolved and cream just comes to a simmer. Remove immediately from heat; stir in softened gelatin until completely dissolved. Set aside; let cool 5 minutes.
Transfer cream mixture to bowl. Add creme fraiche; whisk until blended. Whisk in buttermilk, 1/4 tsp. salt, vanilla, and lemon juice. Strain mixture. Stir in peel.
Spoon custard into 8 serving dishes. Cover with plastic wrap; refrigerate until set, 2 hours or overnight. Makes 8 servings.