In a large heavy-bottomed pot or Dutch oven over medium heat, add diced bacon. Cook, stirring occasionally, until fat renders and bacon is crisp (about 8–10 minutes). Using a slotted spoon remove bacon to a paper-towel-lined plate, leaving the rendered fat in the pot. Reserve cooked bacon for garnish and mix-in later.

Sauté aromatics

Lower heat to medium-low. Add butter and 1 tablespoon olive oil to the bacon fat. When butter foams, add diced onion, celery, and carrots. Sauté, stirring occasionally, until softened and translucent, about 6–8 minutes. Add minced garlic and cook 30–45 seconds more until fragrant.

Make roux

Sprinkle the flour over the softened vegetables and stir to combine, cooking for 1–2 minutes to remove the raw flour taste. The mixture should thicken slightly and coat the vegetables.

Deglaze & build broth

Slowly add the white wine while scraping the bottom of the pot to release any browned bits. Allow the wine to reduce by half, about 2–3 minutes. Then add the fish or chicken stock, whole milk, thyme sprigs, and bay leaf. Stir to combine.

Simmer

Bring the pot to a gentle simmer. Add the cubed potatoes. Partially cover and simmer until potatoes are just tender, about 12–15 minutes. Stir occasionally to prevent sticking and to help the potatoes release a bit of starch for body.

Seafood & Proteins

Prepare seafood

While potatoes simmer, pat cod, scallops, and shrimp dry with paper towels and lightly season with 1/2 tsp salt, 1/2 tsp pepper, and 1/2 tsp Old Bay seasoning.

Add seafood in stages

When potatoes are tender, reduce heat to low. Remove and discard thyme sprigs and bay leaf. Gently stir in the cod pieces and scallops. Simmer gently (do not boil) until the scallops and cod are opaque and cooked through, about 4–6 minutes depending on thickness. Add the shrimp during the last 2–3 minutes—cook just until shrimp turn pink and curl. If using frozen corn, stir it in with the shrimp to heat through.

Finish with cream

Stir in the heavy cream and reserved crispy bacon (reserve a tablespoon for garnish if desired). Heat for 1–2 minutes on low to warm through; do not boil after adding cream to avoid breaking the dairy.

Finishing & Seasoning

Taste the chowder and adjust seasoning with the remaining 1 tsp kosher salt (or to taste), remaining black pepper, and up to 1/2 tsp Old Bay if desired. Stir in chopped parsley, lemon juice, and optional chives. Remove from heat and let rest 3–4 minutes to meld flavors.

Serve

Ladle chowder into warmed bowls and garnish with reserved crispy bacon, extra parsley, and an additional drizzle of cream or a grind of pepper if desired.