Before starting, prep the seafood. This includes cleaning, peeling, and removing the tails from the shrimp and defrosting and draining the clams.
Add the butter to a large pot over low–medium heat. Once melted, add the celery, shallots, garlic, carrots, thyme leaves, and cayenne pepper. Sauté for 3–4 minutes, until the celery begins to soften and the garlic and shallots are soft and fragrant. If the garlic begins to brown, lower the heat.
Add the tomato paste and cook for 4-5 minutes, mixing every minute or so to ensure even toasting and to avoid burning.
Then add the flour and stir to incorporate. Because of the flour-to-butter ratio, the mixture will be a bit thick and on the drier side. Once combined, add the drained can of corn and mix to incorporate.
Add the seafood stock and chicken broth. Mix vigorously to incorporate the flour into the liquid without any clumps.
Add in the potatoes and cover the pot with a lid. Increase the heat to medium to bring the soup to a simmer then continue to simmer on low heat for 20 minutes or until the potatoes are almost tender (*check around the 17 minute mark).
Pour in the heavy cream and bring the pot back to a gentle simmer. Add the seafood and cook for another 5 minutes, or until the shrimp are fully cooked. Serve!