Place peppers on sheet pan and broil for 2 to 3 minutes on each side, or until the skin blackens.
Remove the peppers from oven and place in a bowl covered in foil or cling wrap. Alternately, place in a heat-safe, zipper-locked bag. Allow peppers to steam in the container until they are cool to the touch. Once cool, lift blackened areas from poblanos to peel skins off peppers.
Carefully slit the lengthwise along one side of each pepper, to create an opening for stuffing, taking care not to puncture through both sides. Remove seeds from within and discard.
Set oven temperature to 400 degrees F.
Brown ground pork chorizo sausage in a skillet over medium heat. Discard excess grease.
Add tomato paste, cumin, chili powder, onion powder, salt, and water to skillet and mix well. Bring to a boil, the reduce heat to low and simmer until excess liquid cooks off.
Remove skillet from heat and stir in mushrooms.
Stuff mixture into the hollowed out peppers and place on a casserole dish lined with parchment paper or lightly greased. Bake for 10 to 15 minutes.
Serve garnished with cotija cheese, crema, and cilantro divided between the peppers.
Grilling information: Char peppers on grill grates over high, direct heat; grill after stuffing in a cast-iron pan on medium-high over indirect heat for 15 minutes.Nutrition information is based on a single serving and is provided as a convenience for Ketogasm readers. Data may vary based on brand and recipe variation.