Cook the Bacon: Heat a skillet over medium heat. Cook bacon for about 3 minutes per side until crisp and browned. Transfer to a plate lined with paper towels, and reserve 2 teaspoons of the bacon fat if desired for the breadcrumb topping. Chop the bacon into small bits, setting aside ½ cup for the filling.
Preheat the Oven: Set the oven to 400°F and place a rack in the center.
Prepare the Filling: In a medium bowl, combine the cream cheese, cheddar cheese, chives, garlic, salt, and pepper. Use a fork to mix everything until smooth and fully combined.
Prepare the Jalapeños: Slice the jalapeños in half lengthwise and remove the seeds and membranes using a spoon (consider wearing gloves for this step). Discard the seeds.
Stuff the Jalapeños: Fill each jalapeño half with the cream cheese mixture, leveling it with the sides. Arrange them in a single layer on the baking sheet.
Prepare the Topping: In a separate bowl, combine the breadcrumbs and melted butter (or reserved bacon fat). Stir until the crumbs are moistened. Mix in the chopped bacon and sprinkle about 1 teaspoon of the crumb mixture over each jalapeño.
Bake: Bake the poppers for 17–20 minutes, or until the jalapeños are tender and the breadcrumb topping is golden brown.
Cool and Serve: Allow the poppers to cool for 10 minutes before serving. Garnish with additional chives for a finishing touch.