In a small bowl, whisk the matcha powder with 1 tablespoon warm water until completely smooth with no lumps. This creates a paste that will blend evenly into the yogurt.
In a medium bowl, combine the Greek yogurt, matcha paste, honey, and vanilla extract. Fold together gently until the color is uniform and no streaks remain. Taste and add more honey if you prefer it sweeter.
Take 4 clear glasses or mason jars. Spoon 1/4 cup of the matcha yogurt into the bottom of each glass, spreading it evenly.
Add a layer of granola over the yogurt in each glass, using about 3 tablespoons per parfait. Press down very gently to create a compact layer.
Top with another layer of matcha yogurt, then scatter fresh berries over the yogurt in each glass.
Add a final thin layer of granola on top for crunch, then sprinkle with toasted sliced almonds.
Garnish each parfait with a small mint leaf and an optional drizzle of honey. Serve immediately, or refrigerate uncovered for up to 30 minutes before serving.