In a large pot cook the bacon to a soft doneness on medium-high heat, 5-8 minutes
Remove the bacon with a slotted spoon, set aside and drain most of the grease, leaving 1-2 tbsp of grease in the pot
Toss the beef in the flour and pepper, then add the beef to the pot and brown- 5-8 minutes
Use the slotted spoon to remove the meat from the pot and set aside
Add the vegetables and garlic to the pot and saute til the onions are soft, about 5 minutes
Add the thyme and the Guinness and bring to a boil on high heat, scraping the bottom of the pan to get all the brown goodness.
Add the broth and HP and wait for the liquid to return to a boil.
Add the meat and bacon back to the pot, reduce the heat to low and simmer uncovered on low for 2 1/2 - 3 hours. The liquid should be lightly bubbling regularly the whole time. When it's done the ingredients should still be covered in the liquid, but it should be thick like a gravy.
Preheat the oven to 300F
Line a pie dish with 1 roll of pie dough and brush the dough with the mustard.
Spoon the filling into the dough, brush the rims of the dough with the beat egg, then cover with the other roll of dough
Press along the edge of the rim to seal the pie, cut an X in the center and brush the whole pie top with more egg.
Bake at 300F for 30 mins, let sit for 5 mins then serve.