Tourtiere

In a large bowl, whisk flour and salt. Add shortening and, using your fingertips, blend into flour until small pea-sized pieces remain. Add water and gently mix until dough comes together.

Turn out dough onto a cutting board. Divide into 2 (8-ounce) disks. Wrap dough in plastic and chill at least 30 minutes or up to 3 days.

In a large pot, season potatoes with 1 tablespoon salt, then cover with cold water. Bring to a boil over high heat and cook until fork-tender, 8 to 10 minutes. Drain and transfer half of potatoes to a medium bowl. Mash remaining potatoes in pot.

Meanwhile, in a large skillet over medium-high heat, heat oil and butter. Add onion, celery, and garlic; season with 1 teaspoon salt. Cook, stirring occasionally, until onions are translucent and celery is tender, 5 to 6 minutes.

Add rosemary, nutmeg, allspice, cinnamon, and cloves. Cook, stirring, until spices are warmed through, about 30 seconds. Add coarsely ground and finely ground pork; season with remaining 2 teaspoons salt. Cook, stirring to break meat into pieces with a wooden spoon, until pork is no longer pink, 6 to 8 minutes.

Remove from heat and stir in mustard and mashed potatoes. Fold in remaining cubed potatoes, making sure not to break into pieces. Let cool at least 15 minutes.

Add bread to mixture

Meanwhile, roll out 1 dough disk to a 10" to 11" round. Place in a 9" (2"-deep) pie dish or large cast-iron skillet. Tuck in edges and refrigerate until cold, about 15 minutes.

Preheat oven to 375°. Roll remaining disk to another 10" to 11" round. Pour filling into pie dish, then place second round on top to cover. Seal by tucking edges under, then crimp edges with your fingertips. Brush top and edges of dough with beaten egg.

Bake pie until crust is golden brown, 45 minutes to 1 hour. Let cool before slicing.