Preheat the oven to 375°F and lightly grease a loaf pan.
In a large bowl, combine the ground turkey, pesto, breadcrumbs, egg, onion, garlic, salt, and pepper. Mix just until everything is evenly distributed.
Press half the turkey mixture into the bottom of the loaf pan in an even layer.
Lay the mozzarella log lengthwise down the center of the meat mixture.
Cover the mozzarella completely with the remaining turkey mixture and smooth the top.
Bake for 50 to 55 minutes until the internal temperature reaches 165°F in the meat.
Let the meatloaf rest for 10 minutes before slicing to serve.