Add dry ingredients to bowl of a food processor and pulse to combine.
Add butter cubes.
Add water gradually (approx. 1 tbsp at a time.) You might not need all of the water. Continue to pulse until crumbs become wet and begin to stick together, but do not over-process. It should not form a dough ball.
Dump crumby pie crust mixture onto a floured work surface and form two balls of equal size.
Shape into two discs. Cover each disc with plastic wrap and refrigerate for at least 2 hours.
Braised Short Ribs
Prepare the onion, carrots, shallots, garlic, and celery and set aside. Preheat oven to 325°.
Season the short ribs on all sides with salt and pepper.
Preheat a dutch oven or braiser on the stovetop over medium-high heat.
Coat the bottom of the pan in small amount of olive oil.
Brown short ribs for 2 minutes per side. Remove and set aside.
Add 1 tbsp butter to the pot. Transfer the onion, carrots, shallots, garlic, and celery to the pot.
Cook the vegetables, stirring occasionally, until the onions are caramelized.
Deglaze the pot with about 1 cup of the red wine.
Return the short ribs to the pot.
Add the beef stock and remaining red wine. The liquid should cover the short ribs by half.
Transfer the pot to the oven and cook covered for 2½ hours. Check every 45 minuets to 1 hour. The liquid should reduce by a lot, but add more if it begins to completely dry up. By the end, there should be some liquid, but it will have reduced by 50% to 75%.
Add rosemary, thyme, and optional saffron, ensuring they are at least partially submerged in the liquid (also OK to be completely submerged).
Remove the lid and cook uncovered for 15 minutes. Move on to the next steps while the short ribs are finishing.
Preheat oven to 375°.
Meanwhile, peel potatoes and cut into a small dice. Transfer potatoes to a saute pan with 1 tbsp butter. Cook over medium-high heat, stirring frequently. (Move on to the next step while potatoes are cooking, when 15 minutes of uncovered short rib cooking time is up)
Remove the short ribs from the oven. Set short ribs aside on a plate to rest. Do not discard the veggies and liquid in the pot.
Use a slotted spoon, remove the veggies from the short rib pot and transfer them to the pan with the potatoes. Stir to combine. Continue to cook until potatoes are cooked through, then set aside.
Remove all of the meat from the short ribs and discard the pieces of fat. Set aside.
Place pot with the braising liquid onto the stovetop and heat on high to bring to a boil. Combine 1 tbsp cornstarch with 1 tbsp very cold water. Stream the cornstarch mixture into the braising liquid, whisking constantly. The liquid should thicken quickly. Remove pot from heat.
Add the short ribs and vegetables to the pot with the thickened braising liquid and stir until everything is well-combined.
Grease a large pie pan and dust with flour. Roll out pie crust for the bottom of the pie onto a well-floured surface. Transfer the pie crust to the pie pan. Poke a few sets of holes in the bottom of the crust using a fork (and use a pie bird if you have one).
Roll out the pie crust for the top of the pie on a well-floured surface.
Transfer the pot pie filling to the pie pan.
Add the top crust, pinching the edges together to seal. Use a knife or kitchen shears to trim the excess crust from the edges.
Cut slits in the top of the pie crust to vent.
Whisk together 1 egg and 1 tbsp water. Use a pastry brush to coat the pie crust in the egg wash mixture.
Cover the edges of the crust in aluminum foil to prevent burning.
Transfer the pie to the oven. Cook for about 30-50 minutes until the crust is golden.