Combine ground turkey, panko, 1/4 cup of pesto, half the minced garlic, grated parmesan, water, kosher salt, black pepper, and egg in a large bowl. Mix until just combined. Form meatballs using a heaped tablespoon or a 1.5-tablespoon scoop. Roll them briefly in your palms to smooth them, and space them out on the prepared sheet pan.