1. Boil the potatoes in a large pot of salted water until they're tender, then drain and set them aside.

2. Peel the onion and chop it finely. Take the dried tomatoes packed in oil and chop them up as well.

3. In a small skillet, sauté the chopped onion and dried tomatoes in butter over medium heat until the onion is soft and translucent.

4. Next, add a sprinkle of thyme, 60ml (1/4 cup) of white wine, and 120ml (1/2 cup) of heavy cream to the skillet. Bring the mixture to a boil, then reduce the heat to low and simmer until the sauce has thickened slightly.

5. Add the cod fillets to the skillet and poach them in the sauce over low heat until they're cooked through. You're aiming for an internal temperature of about 52°C (125°F). Every now and then, spoon some of the sauce over the fish to keep it moist.

6. Once the cod is cooked, add the fresh tomatoes and chopped basil to the skillet. To serve, place the cod on a plate, spoon the wine sauce over the top, and serve with boiled potatoes on the side.