my italian mil, frys them in hot oil, then drains them. adds some tomato sauce to a little of the oil, and some fresh basil, some salt, maybe some garlic. cooks the sauce a few minutes and then adds the peppers back. it is delicious. but don't cook the peppers too long or they get very bitter.
I've used them to make chile rellenos. The peppers are stuffed with some cheese, beans, or whatever you want and then fried in an egg batter. You could do a search to find the recipe or I can dig it up if you are interested.