Preheat your oven to 350°F (175°C).
In a mixing bowl, combine the Greek yogurt, honey, vanilla extract, and cinnamon. Stir until well blended and smooth.
Transfer the yogurt mixture into a baking dish, spreading it evenly.
Scatter the mixed berries on top of the yogurt mixture.
Bake in the preheated oven for 20-25 minutes, or until the edges are slightly golden and the berries are bubbling.
Remove from the oven and let it cool for about 10 minutes.
If desired, sprinkle granola on top before serving and garnish with mint leaves.