I came up with this recipe after a power outage forced us to throw away or use up quickly most of our food. I use small pork roasts because we have a small family but, of course, you can adjust the seasonings and veggies to fit your family/roast.
Mix the cumin, oregano, salt, pepper and oil to make a liquid-y paste and rub on one side of the pork roast. let him hang out for a little while.
Turn on the broiler and put a stick (aka, not non stick) pan on the element and start heating it up so it gets pretty hot.
Put the poblano and bell peppers under the broiler, turning occasionally to roast.
While the peppers are roasting, dice the onion, garlic and sweet potato. the sweet potato should be in pretty big chunks so that it holds up during cooking.
When the peppers are done roasting, let them cool a little while you brown the roast. put the olive oil in the hot pan and follow up with the roast, unseasoned side down. let that get very nice and caramelized then flip to caramelize the seasoned side (the spices will burn, that's why you should do the unseasoned side first, it cools the pan a little, also, be aware that the seasoned side takes a lot less time).
Deglaze the pan with a little water and pour the resulting broth into the crock pot.
Peel the peppers (the skin should just come right off) and cut into big squares (about an inch or so -- well, however you want I guess, just cut them up).
Throw everything in the crock pot, and cook for about 7 hours on low.