In a small bowl, stir together lemon juice and gelatin. Let stand until softened, about 5 minutes.
In a medium saucepan, combine cream, buttermilk, sugar, and zest. Cook over medium heat, stirring occasionally, until sugar is dissolved. When bubbles form around edge of pan, turn off heat, and stir in gelatin mixture, stirring until dissolved. (If gelatin doesn’t completely dissolve in 3 minutes, return to heat, and warm gently until dissolved.)
Pour mixture into 8 (4-ounce) serving dishes. Refrigerate, uncovered, for at least 4 hours. Top with Candied Lemon Curls. Garnish with mint, if desired.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/lemon-buttermilk-panna-cotta/