Heat the EVOO in a deep skillet with a lid or a Dutch oven over medium-high heat. Add the pancetta and render, about 3 minutes. Add the Fresno chili pepper, garlic, celery, shallot, thyme, bay leaf, salt and pepper. Stir to soften, 5-6 minutes, then add the sherry and reduce by half. Add the stock and tomatoes, breaking them up with a spoon or potato masher. Stir in the basil and simmer to thicken and combine the flavors, 8-10 minutes.
Season the cod and crab with seafood seasoning and slide the fish into the sauce. Cover and cook until the fish is opaque, 8-10 minutes; add the crab and heat through. Serve in shallow bowls with bread for mopping.