Add the milk to a medium saucepan and sprinkle the gelatin on top. Let stand for 3-5 min or until gelatin is softened and bloomed.
Transfer the saucepan to the stove, over medium-low heat, cook and stir until gelatin dissolves, about 5 minutes, but do not bring to a boil.
Still over medium-low heat, add the heavy whipping cream, sugar, vanilla and a pinch of salt. Continue stirring for about 5 minutes, until sugar is fully dissolved, but do not boil. Remove from heat and let cool 5-10 minutes.
Add the yogurt in a medium bowl and whisking constantly, gradually add the warm cream into the yogurt, little by little. Whisk until completely smooth and fully combined.
Divide the mixture between 6 wine glasses let cool to room temperature and after that refrigerate until fully set, which will take 4 to 6 hours.
How to Make Berry Sauce:
In a small saucepan over medium heat, combine 1 cup of berries, the lemon juice, zest, and sugar. Bring to a low boil and stirring cook for about 5 minutes or until the sugar is fully dissolved and the mixture looks syrupy.
Stir in the remaining 1 cup of fresh berries and remove from heat.
Let the sauce cool to room temperature.
Scoop it over the chilled Panna Cottas, top with more fresh berries and fresh mint leaves before serving.