Step 1: Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper for easy cleanup.
Step 2: Prepare the jalapeños: Wearing gloves, carefully slice each jalapeño in half lengthwise. Use a small spoon or melon baller to scrape out the seeds and white membranes. Discard seeds and membranes. (Remember, removing more seeds and membranes reduces the heat.)
Step 3: Make the filling: In a medium bowl, combine the softened cream cheese, shredded cheddar cheese, finely diced cooked shrimp, and Cajun seasoning. Mix well until all ingredients are evenly incorporated.
Step 4: Stuff the jalapeños: Generously fill each jalapeño half with the shrimp and cheese mixture, mounding it slightly. Arrange the stuffed jalapeño halves on the prepared baking sheet.
Step 5: Prepare the topping: In a small bowl, combine the panko breadcrumbs and melted butter. Stir until the panko is evenly coated.
Step 6: Add the crispy topping: Sprinkle the buttery panko mixture evenly over the top of each stuffed jalapeño.
Step 7: Bake: Bake for 20-25 minutes, or until the jalapeños are tender, the filling is bubbly, and the panko topping is golden brown and crispy.
Step 8: Garnish and serve: Carefully remove from the oven. If desired, garnish with fresh chopped chives or green onions. Let cool slightly before serving. Enjoy your fiery and flavorful appetizer!