Make the crust: Form the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 30 minutes.
Make the filling: In a large skillet, brown the ground pork and beef over medium heat. Drain off any excess grease. Add the onion, garlic, thyme, allspice, nutmeg, cloves, salt, and pepper and cook until the onion is softened, about 5 minutes. Stir in the cream and mashed potatoes and cook until heated through, about 2 minutes.
Assemble the pie: Preheat the oven to 375 degrees F (190 degrees C). On a lightly floured surface, roll out half of the dough into a 12-inch circle. Transfer the dough to a 9-inch pie plate, leaving a 1-inch overhang. Pour the filling into the crust. Roll out the remaining dough into a 10-inch circle. Place the dough over the filling, crimping the edges to seal. Cut a few slits in the top crust to allow steam to escape.
Bake: Bake in preheated oven for 1 hour, or until the crust is golden brown and the filling is bubbling. Let cool for at least 30 minutes before serving.