Combine the olives, rosemary, and red pepper flakes in the center of 1 or 2 large sheets of aluminum foil. Fold the foil to enclose the olives in a pouch.
Heat oven to 400° F. Bake for 30 minutes. Serve warm.
This simple yet outstanding recipe makes an appearance at all of my holiday parties. The aromas fill the kitchen so nicely. I highly recommend it.