How to Make It
Pour buttermilk into a large freezer-safe bowl; freeze overnight or until buttermilk is solid.
Place a colander lined with cheesecloth in a bowl. Release buttermilk from bowl into colander; thaw at room temperature about 4 to 6 hours.
Place berries in a large bowl; sprinkle with 2 tablespoons sugar. Add vinegar; toss gently.
Transfer strained buttermilk to a mixing bowl, reserving whey. If needed, whisk in a small amount of reserved whey, 1 teaspoon at a time, until curd is spreadable and has a thick sour-cream consistency. (Reserve the remaining whey for another use, or discard.) Add remaining 1/4 cup sugar, stirring with a whisk. Divide curd evenly among 8 dessert bowls. Arrange berries over curd. Just before serving, sprinkle evenly with honey granules and garnish with fresh mint leaves.
Piccolo, Minneapolis, MN