Melt butter in a large pot over medium heat. Add onion, garlic, celery, and carrots. Cook for 4–5 minutes until vegetables soften and become fragrant.
Stir in diced potatoes and flour, coating everything evenly. Gradually pour in chicken broth while stirring to prevent lumps. Simmer until potatoes are tender, about 10–15 minutes.
Reduce heat and stir in heavy cream, smoked paprika, thyme, salt, and pepper. This creates the rich, velvety base that makes the chowder irresistible.
Gently fold in shrimp, scallops, and white fish. Simmer for 5–7 minutes until seafood is fully cooked but still tender. Avoid overcooking to maintain texture.
Taste and adjust seasoning if needed. Sprinkle with fresh parsley or chives before serving. This final touch adds freshness and makes your chowder look beautiful.