Wash collard greens well, remove the stems, and slice into ribbons. Prep all vegetables by dicing potatoes and chopping onion, garlic, tomatoes, and celery.
In a large Dutch oven, heat the olive oil or butter over medium heat. Add the onion, garlic, and celery and cook until softened.
Season the mixture with smoked paprika, thyme, pepper, crushed red pepper flakes, and salt. Add Creole seasoning if using.
If adding meat, use fully cooked, ready-to-eat smoked sausage, smoked turkey, or ham hock. Check the package: smoked does not necessarily mean cooked. Cook any raw or cook-before-eating product separately according to its package directions before adding it; that cooking time is additional. Stir the cooked meat into the pot and cook briefly to deepen the flavor.
Add the collard greens and tomatoes. Cook until the greens begin to wilt.
Pour in the chicken broth. Add potatoes and bay leaf. Bring the pot to a gentle boil.
Reduce heat, cover, and simmer 30–40 minutes until potatoes are tender and greens are soft. If meat is included, check that the meat and stew reach 165°F with a food thermometer before serving.
Taste and adjust seasonings. Add apple cider vinegar or lemon juice for brightness. Serve warm.