In a food processor whizz together half the pine nuts and all of the garlic for 20 seconds, then add the coriander, green chilli, the lemon zest and a good pinch of salt and whizz for a further 20 seconds. Next add the Parmesan and slowly pour in the olive oil, lemon juice and 3 tbsp water (if cooking for 4) whilst the processor is running. Season to taste. Note - you can add 1-2 tbsp more water if you prefer a runnier dressing.

Place the salad leaves, tomato, avocado, remaining pine nuts and mozzarella balls in a large salad bowl and toss together with most of the pesto dressing.

Rub the tuna steaks with a drizzle of olive oil and season generously. Heat a griddle plan over a medium-high heat and when hot add the tuna. Cook until the colour changes to halfway up the side of the tuna, then turnover and cook in the same way as the first side.

Serve the grilled tuna steak on top of your caprese salad with a wedge of lemon, and the remaining pesto dressing in a small jug on the table for those who wish more.