Cook bacon in a large pot over medium heat. Add chopped onion and cook until soft and translucent. Remove bacon and onion, setting aside, and leave bacon fat in the pot.

Add peeled and cubed potatoes to the pot with bacon fat. Pour in enough water to cover potatoes and cook for 5-10 minutes until potatoes start to soften.

Place fresh haddock on top of potatoes. Cook until fish flakes easily with a fork, then remove any skin.

Mix flour with a little water to make a paste, then stir into the pot. Bring to a brief boil to thicken the chowder.

Reduce heat, pour in whole milk, and add reserved bacon and onion. Heat gently without boiling to allow flavors to meld.

Season with salt and pepper to taste. Serve steaming hot in bowls.