Preheat a large frying pan or skillet on a high heat.
Rub fish with a little oil. Season.
Pop fish into the pan and cook for 2-3 minutes on the first side.
Meanwhile, process cashews, garlic, lemon juice, 2 tablespoons water and 2 tablespoons extra virgin olive oil until you have a smoothish sauce. Taste and season.
Turn fish when well browned and cook on the second side for another 2-4 minutes or until cooked through.
Divide sauce between 2 plates. Top with fish and serve leaves on the side.