Preheat oven to 400°F with a racks the upper thirds. Soak bread in milk in a small bowl until softened, about four minutes.
Cook pancetta, onion, and garlic in one tablespoon oil with 1/2 teaspoon each of salt and pepper in a large skillet over medium heat until onion is softened, about 6 minutes. Cool slightly.
Squeeze bread to remove excess milk, then discard milk. Lightly beat egg in a large bowl, then combine with turkey, 1 tablespoon tomato paste, pancetta mixture, bread, and parsley. Form 12 meatballs and arrange on baking rack on top of a roasting pan.
Stir together remaining tablespoons of tomato paste and oil and brush over meatballs (the paste/oil does not mix in any cohesive manner, but just smoosh it on , bake in upper third of oven until meatballs are cooked through, 20 to 25 minutes .