Preheat the oven to 375.
Line a large baking sheet with parchment paper.
In a large bowl, combine all ingredients for the turkey except the mozzarella. Mix until well combined.
Scoop a heaping tablespoon sized ball of turkey and stuff with cheese. Be sure to roll it well so that there are no cracks. This way, cheese will not escape during baking.
Arrange turkey balls on one side of the pan. Then arrange the peppers on the other side, in a single layer.
Drizzle peppers with olive oil, salt and pepper.
Bake for 25 minutes until peppers are blistered and balls are cooked through.