Preheat your oven to 400 degrees Fahrenheit. Line a baking sheet with parchment paper.
Prepare the jalapeños: Wearing gloves, slice each jalapeño in half lengthwise. Use a small spoon or knife to carefully remove the seeds and white membranes. Rinse the pepper halves under cold water to remove any remaining heat. Pat them completely dry.
Make the filling: In a medium bowl, combine the softened cream cheese, crabmeat, Parmesan cheese, mayonnaise, Worcestershire sauce, garlic powder, and black pepper. Mix until just combined. Do not overmix.
Stuff the peppers: Spoon or pipe the crab mixture evenly into each jalapeño half, mounding the filling slightly.
Prepare the topping: In a small bowl, mix the panko breadcrumbs and melted butter. Sprinkle the breadcrumb mixture evenly over the tops of the filled poppers.
Bake the poppers for 18 to 20 minutes, or until the filling is hot and bubbly and the topping is golden brown.
Remove from the oven and let cool for 5 minutes before serving.
Notes
For less heat, wear gloves when handling the jalapeños and thoroughly remove all white pith and seeds.
If you prefer a crispier exterior, you can briefly broil the poppers for the last 1-2 minutes, watching closely to prevent burning.
Serve with a side of ranch dressing or a light sweet chili sauce for dipping.