Using a food processor, puree 1 cup cilantro leaves, 2 cloves garlic, 2 serrano chiles, 3 tablespoons brown sugar, one 1-inch piece fresh ginger, the grated peel and juice of 1 lime and 1 tablespoon each fish sauce and soy sauce. Wearing rubber kitchen gloves, gently loosen the turkey skin and massage in the paste under the skin.
