
Scrub the fresh clams and snails well. Steam them separately in covered pots with about 1 inch of water until the clams open and the snails are cooked through, about 8-10 minutes. Discard any clams that do not open, strain and reserve the clam cooking liquid, and set aside a few clams in their shells for garnish.



Heat the olive oil in a large soup pot over medium heat. Add the sliced andouille sausage and cook until browned, then transfer it to a plate. Add the butter, onion, fennel, garlic, and lemongrass to the same pot and saute for about 3 minutes, until fragrant and slightly softened.



Sprinkle in the flour, Cajun seasoning, smoked paprika, minced chipotle, salt, and black pepper. Stir constantly for about 2 minutes to cook the flour and bloom the spices, scraping up any browned bits from the bottom of the pot.



Slowly pour in the reserved clam liquid, stirring to prevent lumps. Add enough bottled clam juice or seafood stock to make a generous chowder base, then add the potatoes. Bring to a boil, reduce to a simmer, and cook for about 15 minutes, or until the potatoes are tender.

Stir in the cooked clams, snails, and browned sausage. Add the heavy cream and simmer gently for 5 minutes, stirring often. If you prefer a thicker chowder, stir in a cornstarch slurry a little at a time and simmer until the texture is creamy and spoon-coating.
Taste and adjust the seasoning. Ladle the chowder into bowls, garnish with fennel fronds and reserved shell-on clams, then finish with a drizzle of olive oil. Serve hot with toasted bread.




