Preheat the oven to 400°F. Meanwhile, start on the pesto. Add the parsley and garlic to a food processor. Pulse until it is chopped, scrapping down the sides occasionally. Add in the Parmesan and pine nuts. Pulse twice. Then turn the processor on and slowly drizzle in the 2 1/2 tablespoons of olive oil. Season with salt to taste.

Tear off two 18-x-12-inch pieces of aluminum foil. Fold each in thirds lengthwise, and the reopen. Toss the zucchini slices and tomatoes with a bit of oil and some salt, and then divide between the two packets. Season both pieces of cod with salt and pepper and then place each on top of the vegetables. Spoon a tablespoon of the pesto on to of each.

Bring the long ends of each packet to the middle and fold. Fold up the shorter sides, and crease to make sure nothing will spill out. Place both pouches on a baking tray. Set the tray in the oven and cook for 15 minutes.

Carefully open the packets and slide all the contents into separate bowls. Drizzle with a bit more extra-virgin olive oil and serve.