We love fajitas, but normally I've made them with chicken, using a pack.
This recipe, though, is less hassle than using something like an Old El Paso kit - the prep is about the same, but then you just shove it in the oven and go do something else for 30 minutes. Tasty fajitas, with minimum effort.
You can use casserole chunks, or stir fry strips - whichever you choose, make sure it's decent quality meat otherwise it may come out too chewy.
If you've any left over at the end of the meal, keep overnight, then warm at lunch and put in a sandwich.