In a medium bowl, combine the sliced strawberries, blueberries, and raspberries. If desired, drizzle with honey and gently toss to coat the berries. Set aside.
In serving glasses or bowls, layer 1/4 cup of yogurt at the bottom of each glass.
Add a layer of mixed berries (about 1/4 cup) on top of the yogurt.
Sprinkle 2 tablespoons of granola over the berries.
Repeat the layers until the glasses are filled, finishing with a layer of berries and a sprinkle of granola on top.
Garnish with fresh mint leaves if desired. Serve immediately or chill for up to 30 minutes before serving.