Gather all ingredients. Preheat the oven to 425 degrees F (220 degrees C).
Place potato in a saucepan with enough water to cover. Bring to a boil, and cook until tender, about 5 minutes.
Drain, mash, and set aside.
Meanwhile, crumble ground beef and pork into a large saucepan. Add onion, garlic, mustard powder, thyme, sage, cloves, salt, and black pepper. Stir in water. Cook over medium heat, stirring, until meat is evenly browned.
Remove from the heat and mix in mashed potato.
Ease one pie crust into a 9-inch pie plate. Fill with meat mixture, then top with the remaining pie crust.
Trim any excess dough, then crimp the edges with the tines of a fork to seal.
Prick top crust a few times with a knife to vent steam. Cover the edges of the crust with aluminum foil.
Bake in the preheated oven until crust is browned, about 25 minutes.
