Heat blueberries in a small pan with 1 tablespoon of honey over medium heat for 5 minutes until they burst; let cool.
Zest the lemons first, then juice them into a small bowl, removing any stray seeds.
In a large mixing bowl, combine the Greek yogurt, remaining honey, lemon juice, zest, vanilla, and salt.
Whisk the mixture vigorously until it is completely smooth and the honey is fully incorporated.
Gently swirl the cooled blueberry mixture into the yogurt base with a knife or spatula.
Pour the mixture into a shallow, freezer-safe container or a metal loaf pan.
Place the container in the freezer and stir the mixture with a fork every 45 minutes for the first 2 hours.
Allow the yogurt to freeze undisturbed for an additional 2 hours or until firm enough to scoop.