Preheat the oven to 200 ºC.
Lay frozen Sea Harvest Haddock Fillets onto a baking tray. Place into the oven for 15-25 minutes until cooked through. Alternatively cook in an air fryer for the recommended time.
Set a medium size pot over medium-high heat. Add the oil and butter; allow the butter to melt and the oil to heat and then add the onions, celery and leeks. Fry for 6 minutes until the veggies have softened. Add the garlic and fry for another minute until fragrant.
Add stock and cream and then the potato cubes; cover and simmer for 10-15 minutes until the potatoes are soft. Add the corn and thyme and stir gently to combine so as to not break down the potatoes too much. Simmer for another 5-8 minutes. Flake the cooked haddock pieces into the chowder and stir gently.
Portion into serving bowls and garnish with a little chopped parsley. Serve with crusty bread or salted crackers.