Heat a griddle pan until hot. Brush 1 tablespoon of the oil over the fish steaks and season well with salt and pepper. Add the fish to the pan and cook for 3–5 minutes on each side until just cooked through.
Meanwhile, place the remaining oil with all the other remaining ingredients in a small food processor and whizz until you have a smooth paste.
Spoon the pesto over the fish and serve with a cucumber salad and pitta bread.