1. Roughly tear mint leaves and place with the hazelnuts, garlic and 1 tablespoon of the oil in a food processor and blend for 1-2 minutes
2. With motor still running, gradually pour in the remaining oil until a smooth consistency is achieved. Scrape into a small bowl, stir in the lemon juice, Parmesan cheese and seasoning to taste. (Alternately place the mint, nuts and garlic and 1 tbsp of oil in a mortar and pound to a paste, gradually work in the rest of the oil and then stir in the lemon juice, cheese with seasoning to taste.)
3. Wipe or lightly rinse the turkey and make 3 deep slashes across each fillet, sprinkle with 2 tablespoons of lemon juice and leave lightly covered for at least 15 minutes.
4. When ready to cook, preheat the grill and line the grill rack with tin foil. Brush the prepared Pesto over the turkey breasts and place under the preheated grill.
5. Cook for 3 minutes on each side, then reduce heat to moderate and continue to cook for 13-15 minutes on each side, then thoroughly cooked. Brush occasionally with the Pesto. Pour over the remaining lemon juice and serve garnished with mint sprigs, lemon wedges with freshly cooked pasta or your choice.
For the pesto
For the turkey