Step 1
In a medium bowl, cover the cod with 2 quarts of water. Refrigerate for 24–36 hours, changing the water two or three times while soaking.
Step 2
Drain the cod and transfer to a small pot. Cover with 2 quarts of water and bring to a boil. Turn the heat to medium and simmer until it flakes easily, about 10 minutes. Drain, then transfer to a bowl and use a fork to flake into large chunks.
Step 3
To a large skillet set over medium-high heat, add the oil, thyme, garlic, onion, green bell pepper, red bell pepper, tomato, and chile and cook, stirring occasionally, until soft, about 10 minutes. Add the cod, scallions, and ackee and cook, stirring gently to keep the cod and ackee in large pieces, until hot, about 5 minutes. Season to taste with salt and black pepper.