Dissolve gelatin in 1/2 cup water. Let stand 5 minutes.
Heat heavy cream and sugar in a small saucepan over medium heat until mixture reaches 160 degrees F, about 5 minutes.
Remove from heat. Stir in lemon juice, zest, vanilla and salt. Heat gelatin mixture in microwave oven on high 10 to 15 seconds or until it is liquid. Stir into cream mixture. Divide among 8 small custard or coffee cups; refrigerate overnight.
Peel lemons; do not remove any of the white pith. Cut peel into small strips. Heat 1 cup of the sugar, water and lemon peel in a small saucepan for 5 to 7 minutes until peel is tender. Drain and spread peel on a plate in one layer; sprinkle with remaining 2 tablespoons sugar. Let dry for 1 hour.
Serve panna cotta topped with Candied Peel, mint and raspberries, if desired. Makes 8 servings.