Melt the butter in a large pot over medium heat.
2 tablespoons butter
Add the onion, garlic, celery, and carrot. Stir frequently and cook for 4-5 minutes, until the onions look translucent (slightly see-through) and the carrots start to soften.
1 small onion, 2 cloves garlic, 2 celery stalks, 1 large carrot
Stir in the diced potatoes and pour in the chicken broth.
2 medium gold potatoes, 3 cups chicken broth
Bring the mixture to a boil, then reduce the heat to low. Cover the pot with a lid and let it simmer for 10-12 minutes. The potatoes are ready when you can easily pierce them with a fork.
Stir in the heavy cream.
2 cups heavy cream
In a small bowl or liquid measuring cup, ladle out 1 cup of hot broth from the pot. (Note 2)Add the flour, one tablespoon at a time, whisking constantly to create a smooth, lump-free mixture. Slowly pour the slurry back into the pot while stirring to thicken the chowder.If it's still not thick enough, stir in a cornstarch slurry (2 tablespoons cornstarch plus 2 tablespoons cold water) and simmer 1-2 minutes longer. Add the shrimp, scallops, and white fish.Reduce the heat to low and simmer gently for 5-7 minutes. Avoid boiling to prevent the cream from curdling (See Note 3). ½ pound medium shrimp, 3-4 large scallops, ½ pound white fish
Stir in the smoked paprika, thyme, and a pinch of salt and pepper.
½ teaspoon smoked paprika, ¼ teaspoon dried thyme, Salt and pepper
Taste the chowder and adjust the seasoning if needed. Let it sit on low heat for 2-3 minutes to allow the flavors to meld.Ladle the chowder into bowls and garnish with fresh parsley or chives.Serve with oyster crackers or crusty bread.