Heat oven to 425 F. Place the bacon in a 9-inch cast iron skillet, then set it over medium-low heat. Cook, stirring occasionally, until the fat has rendered and the bacon has browned on the edges, 7 to 10 minutes.
Meanwhile, in a large bowl, whisk together the flour, salt, pepper and baking powder. In a medium bowl, whisk together the eggs and milk, then whisk the egg mixture into the flour. Stir in the Parmesan and half the chives.
Once the bacon is crisp and brown, raise the heat to medium-high and add the butter, stirring until melted. Pour the batter into the skillet, then quickly arrange the Camembert pieces on top.
Transfer the skillet to the oven and bake until puffed and golden, about 20 to 25 minutes. Sprinkle with the remaining chives and serve immediately.