In a Dutch oven or large saucepan over medium-low heat, cook bacon until almost crispy, about 10 minutes.
Add celery, onion and bell pepper. Sauté until vegetables start to brown, about 8 minutes. Stir in garlic, thyme, bay leaf, and Cajun seasoning until fragrant, about 30 seconds.
Stir in broth and black-eyed peas. Cover and bring to boil; reduce heat and simmer until peas are tender, about 60 to 90 minutes (mine took about 75 minutes to finish).
Remove bay leaf and drain if desired (see notes). Season to taste with salt and pepper. Garnish with scallions and serve with cooked rice if desired (you can top the rice with Hoppin' John or mix the two together).
Bacon: Thick-cut slices of your favorite savory style of bacon works well. If frozen, chop the bacon while it’s frozen (firm but not rock-hard). It’s so much easier and less greasy that way. Diced pancetta or ham are suitable swaps.
Cajun seasoning: Use store-bought or to make your own Cajun Seasoning, stir together 3 tablespoons smoked or sweet paprika, 2 tablespoons garlic powder, 2 tablespoons Italian seasoning, 2 tablespoons salt, 1 tablespoon cayenne pepper, 1 tablespoon dried thyme, and 1 tablespoon onion powder. You'll just need 1/4 teaspoon for this recipe, so if you don't want to go to the effort, simply trade in 1/4 teaspoon cayenne pepper.
Black-eyed peas: To soak beans overnight, add 4 quarts water to a large bowl and add 1 pound of rinsed black-eyed peas. Soak at least 8 hours. To quick-soak beans, add 1 pound of rinsed beans to a large saucepan and cover with 3 inches of water. Bring to a boil. Boil rapidly for 5 minutes, then remove from heat, cover, and let stand for 1 hour. (See "Recipe FAQs" for more bean-soaking tips.)