There are many different ways to make this dish, and not just on St. Patrick's Day. In England and Ireland, shepherd's pie is always based on lamb (hence "shepherd"), while ground-beef versions are sometimes called cottage pie instead. At Solas, our authentic Irish pub in Boston, Mass., we serve both lamb and beef versions.
The recipe below calls for the pie to be baked in one large dish, in the traditional manner, but at the restaurant we the serve it in individual portions. We’ll heat up the cast-iron dishes to 400 degrees, add the ingredients, and then broil the top so a crust forms. That way, it arrives to our guests simmering hot.