Gather all ingredients.

To make the crust: Place flour, frozen butter, and salt into the bowl of a food processor. Pulse until butter breaks down to pea size. Stir cold water and vinegar together and drizzle over flour mixture. Pulse until crumbly and holds when pinched. Add more water if too dry.

Form mixture into a ball, flatten to a disc, wrap, and refrigerate for 60 minutes.

To make the spice blend: Mix salt, black pepper, thyme, sage, cinnamon, ginger, nutmeg, allspice, mustard, clove, and cayenne in a small bowl.

To prepare filling: Boil potato with salt until tender (10-15 minutes). Remove potatoes, mash, and set aside while reserving cooking water.

In a skillet, melt butter and sauté onion with salt until golden (10-15 minutes). Add celery, garlic, and spice blend. Stir for 30 seconds.

Add ground pork, beef, and 3/4 cup cooking water to skillet. Cook, stirring, until meat browns, liquid evaporates, and meat becomes tender (45 minutes). Stir in mashed potatoes and let cool to room temperature.

Preheat oven to 375°F (190°C) and roll out dough into top and bottom crusts.

Fill bottom crust with meat mixture, smooth surface, and cover with top crust. Cut slits for steam, crimp edges, and brush with egg wash.