Pre-heat grill.

Butterfly the chicken breasts in half if large.

Fry gently on one side until chicken looks cooked half way up, then turn over and fry for the same amount of time until just firm to touch (with a utensil). Take off heat.

Spread a heaped teaspoon or so of pesto on each piece of chicken and then layer on the tomatoes and mozzarella.

Season and drizzle with olive oil.

Put pan under the grill until cheese has melted.

Serve on a bed of pasta (pour over pan juices) with a mixed green salad.