Chowders typically are thicker than other soups, more similar to a stew, typically including sautéed vegetables like potatoes and onions thickened with cream or flour.
Char the Anaheim peppers over gas flame or in broiler until blackened on all sides. Enclose the peppers in paper or plastic bag for 10 minutes. After roasting the poblanos, carefully peel off the charred skin. Chop the peppers into ½” pieces.
Heat a large pot over medium heat, add the olive oil and heat through. Add the onion and sauté, stirring occasionally, until soft and opaque, about 5 minutes. Add the garlic, cooking until fragrant, about 30 seconds.
Add the butter and allow to melt then stir in the flour and let cook, continuing to stir until the mixture is a pale golden brown, about 1 minute. Stir in the chicken stock then add the corn, potatoes and chilies. Bring to a simmer, cooking until the potato is tender, about 20 minutes.
Once the potatoes are tender add the fish, shrimp and clams and cover, cooking until the fish is cooked through and the clams open, about 6 minutes. Discard any clams that don’t open.
Stir in the cream and ladle the chowder into bowls, Garnish with chives and serve.
Notes
Finish the chowder with a small squeeze of fresh lime or a pinch of citrus zest right before serving. This brightens the flavors and balances the richness of the corn and cream without altering the cooking steps.