Preheat your oven to 375°F (190°C) and lightly grease a baking dish to prevent the peppers from sticking.
Prepare the bell peppers: Wash them under cold water, then cut off the tops and carefully remove the seeds. Ensure you create enough space for the stuffing.
(Optional) Blanch the peppers: For a softer texture, you can blanch the prepared peppers in boiling salted water for 3-4 minutes. Afterward, immerse them in ice water to halt the cooking process, then let them cool.
Sauté the aromatics: In a skillet, heat 1 tablespoon of olive oil over medium heat. Add the chopped onion, minced garlic, chopped celery, and (if using) chopped mushrooms. Sauté for about 5-7 minutes until the onions are translucent and fragrant.
Prepare the stuffing: In a mixing bowl, combine 8 oz of lump crab meat, 8 oz of cooked and chopped shrimp, ½ cup of panko breadcrumbs, ¼ cup of chopped fresh parsley, 1 tablespoon of lemon juice, 1 teaspoon of dried thyme, ½ teaspoon of paprika, along with salt and pepper to taste. Carefully fold the sautéed mixture into the seafood filling.
Stuff the peppers: Generously fill each bell pepper with the seafood mixture, pressing gently to ensure it’s packed well. Top each stuffed pepper generously with 1 cup of shredded cheddar cheese.
Add moisture: Pour ½ cup of chicken broth (or vegetable broth) into the greased baking dish, creating a steaming environment for the stuffed peppers.
Cover and bake: Cover the baking dish tightly with foil and bake in the preheated oven for about 20-25 minutes or until the peppers are tender.
Broil for finish: Remove the foil and broil the stuffed peppers on high for an additional 2-3 minutes, or until the cheese is bubbly and golden.
Cool and serve: Allow the stuffed peppers to cool slightly before serving. Pair them with rice or your favorite dipping sauce for an extra layer of enjoyment!