Preheat your oven to 400F and move the rack to the top third of the oven.
Cook the bacon in a skillet over medium-high heat until crispy (about 10 minutes).
Meanwhile, slice the jalapeno peppers in half lengthwise and remove the seeds and the ribs (leave some pith/membrane in for extra spice if you like). I recommend using rubber gloves when handling hot peppers.
Add the cream cheese to a medium bowl, along with the garlic powder, scallions, and cheddar cheese. Once the bacon is cooked, spoon it out of the pan and into the bowl (leave most of the bacon fat in the pan, but adding a little to the cheese mixture adds more flavor). Mix/mash together until you've got a smooth mixture.
Spoon the filling into each jalapeno pepper half, pressing it down a bit so the surface is even for the panko topping, and place on a foil lined baking sheet.
Add the butter to a small bowl and melt it in the microwave, then stir in the panko. Sprinkle over each pepper half (I find it easiest to do this by hand).
Bake the jalapeno poppers, uncovered, for 20-25 minutes, season with salt & pepper if needed, and let them cool for a few minutes before enjoying.