Chop the bacon into 1/2-inch pieces. In a large heavy-bottomed pot over medium heat, add the bacon and cook, stirring occasionally, until crisp and golden, about 6–8 minutes. Use a slotted spoon to transfer the cooked bacon to a paper towel-lined plate, leaving rendered fat in the pot (leave about 1–2 tablespoons).

Lower heat to medium-low and add the butter to the bacon fat. Add the finely diced onion and cook, stirring occasionally, until softened and translucent, about 5 minutes. Add the chopped lemongrass, grated ginger, and minced garlic and cook for 1–2 minutes until fragrant, stirring so they don’t brown.

Vegetables & Starch

Add the diced celery and carrot (if using) to the pot and cook 3–4 minutes to soften. Add the cubed potatoes and stir to coat with the aromatics for 1–2 minutes.

Clams & Liquid

Pour in the clam juice plus broth (total about 3 cups). Add the bay leaf and dried thyme. Turn heat up to medium-high and bring to a gentle simmer. Reduce heat to medium-low and simmer, uncovered, until the potatoes are fork-tender, about 12–15 minutes.

If using fresh clams: while potatoes cook, scrub clams well. Add whole clams to the simmering broth, cover, and cook until clams open, about 5–7 minutes. Remove any clams that do not open. Take opened clams off the half shell, chop coarsely and return the meat to the pot; reserve a few whole pieces in shells for garnish if desired. If using canned clams: drain and reserve the clam juice to add to the pot earlier; add the chopped canned clams to the pot about 3 minutes before finishing so they warm through but don’t overcook.

Cream & Finish

Stir in the coconut milk and the whole milk or half-and-half. Warm gently over low heat—do not boil once dairy is added—to combine and thicken slightly, about 4–5 minutes. Taste and adjust consistency with up to 1/2 cup additional broth if too thick.

Add the cooked bacon back into the pot. Stir in lime juice, chopped cilantro, chives or green onion, sea salt, black pepper, and red pepper flakes if using. Simmer over low heat 2 minutes to meld flavors, then remove the bay leaf.

Ladle chowder into bowls and garnish with extra cilantro, sliced chives, a twist of black pepper, and reserved clam pieces in shell or extra crispy bacon if desired.