Preheat the oven at 375ºF.
Cover a baking dish with aluminum foil. Coat it with olive oil.
Peel and cut the potatoes in cubes. Toss them with olive oil, salt and pepper.
Place them on the baking dish, add 1/3 of the garlic, toss and cook in the oven for 30 minutes or until browned and tender. Turn them over at halfway through.
Season the cod portions with salt and pepper and brush with olive oil. Transfer to a baking dish. Cover the portions with the chopped tomatoes and the chopped basil leaves. Cook in the oven for 10 minutes or until fish flakes easily.
Combine the cod portions with the baked potatoes, add the green beans, lemon juice, the remaining garlic and drizzle olive oil.
Bake it for an additional 10 minutes.
Serve it hot.