Preheat oven to 450 F. At the same time, begin to boil a medium sized pot with six cups of water.
Cut tops off poblanos and slice in half lengthwise. Remove the seeds and membrane.
Place peppers on a baking sheet and roast for 15 minutes.
While peppers are roasting, add cubed sweet potato to pot and boil for 10 minutes.
Drain pot and add sweet potatoes to a bowl with chopped chipotle pepper. Mash and set aside.
Remove peppers from oven and let cool enough to handle.
While peppers are cooling, heat a pan over medium heat.
Once hot, add the sausage and brown for 2-3 minutes. Add the onion, mushrooms and garlic to the pan and cook until softened, about 5 minutes.
Remove from heat and add chopped cilantro and spices.
Spread about two tablespoons of sweet potato into each pepper (you may have a little more or a little less depending on the size of the sweet potato) and top with about two to three tablespoons of sausage mixture.
Return stuffed peppers to the oven for 8 minutes.
Turn oven to broil and cook for an additional 2 minutes.