Set oven rack about 6 inches from the heat source and preheat the oven's broiler. Line a baking sheet with aluminum foil and place peppers on the baking sheet. Cook under the preheated broiler until the skin of the peppers has blackened and blistered, 3 to 4 minutes. Place blackened peppers into a bowl and tightly seal with plastic wrap. Allow peppers to steam as they cool, about 20 minutes.

Preheat the oven to 350 degrees.

Combine the mashed potatoes, half the bacon, cheddar cheese, sour cream, & garlic powder. Season to taste with salt & pepper, if needed.

Remove skins from the roasted poblano peppers. Make a small cut in each pepper and scrape out seeds. Stuff peppers with potato mixture. Bake at 350 for 15 minutes. Remove from the oven & top with the remaining chopped bacon. Garnish with green onions and/or cilantro.