1 medium onion, finely chopped (about 8 ounces; 225g)
4 large ribs celery, finely chopped (about 6 ounces; 170g)
Kosher salt and freshly ground black pepper
2 tablespoons all-purpose flour (about 20g)
1 cup bottled clam juice or fish broth (235ml)
1 quart whole milk (900ml)
1 pound russet or Yukon gold potatoes, peeled and cut into 1/2-inch cubes (450g)
1 bay leaf
2 filets of salmon
Minced fresh herbs such as parsley, dill, or chives, for serving
Combine salt pork or bacon and water in a heavy-bottomed stock pot or Dutch oven over medium heat and cook, stirring occasionally, until water has evaporated and pork has begun to brown and crisp in spots, about 8 minutes.
Add onion, and celery. Season gently with salt and pepper and continue to cook, stirring occasionally, until onions are softened but not browned, about 4 minutes longer. Add flour and cook, stirring, until no pockets of raw flour remain. Stir in clam juice, followed by milk. Add potatoes and bay leaf and bring to a simmer.
Simmer chowder, stirring occasionally, until potatoes are fully tender, about 15 minutes. Stir in fish chunks and simmer just until cooked through, about 3 minutes. Season to taste with salt and pepper.
Serve immediately, garnished with minced fresh herbs.