Don't use a screw type easy out, it will crack aluminum.
Procedure:

If it's sticking out, vice grips.

If it's inside, harder procedure-
1. center punch a dent in the middle of the stud
2. take a small drill bit, drill a pilot hole into dent
3. take the proper size drill bit, drill the ez out hole into stud, don't go too deep- take out another stud and mark the bit with the proper depth if you have to
4. make sure you don't measure on one of the holes that goes to an oil passage
5. use a hammer-in extractor only, screw type will crack the head
6. getting a proper tap T handle really helps if you can't get much depth on the drill hole