- Make up the herb pesto. Put the herbs in a blender with pine nuts, parmesan and olive oil. Blitz.
- Season to taste with salt and pepper and lemon juice.
- Warm it up gently in a saucepan.
- Heat a griddle pan to high, brush with oil.
- Season the tuna on both sides. Cook for two minutes on each side, slightly longer if you want it cooked through (no trace of pink).
- Serve with the pesto on top and some seasonal vegetables.