This casserole is traditionally made with ground lamb.  Many people make this recipe with ground beef however, if you use ground beef it's u003cemu003eu003cstrongu003eactually called Cottage Pie! u003c/strongu003e(You can also replace the meat for a u003ca href=u0022https://www.spendwithpennies.com/easy-lentil-shepherds-pie-vegetarian/u0022u003evegetarian lentil versionu003c/au003e). u003c/emu003eu003cbr/u003eu003cbr/u003eEither way, this crustless meat pie is topped with mashed potatoes and baked until bubbly.