Step 1

Heat a large pot or Dutch oven over high heat and add a few tablespoons of olive oil.

Step 2

Dry the meat with paper towels thoroughly then sprinkle generously with salt and pepper. Add the meat to the pot in batches, cooking to brown on each side. Remove to a plate and continue until all meat is browned.

Step 3

Once the meat has been removed, add the onion, celery and carrots. Cook for 5-7 minutes until they begin to soften. Add the garlic, salt and pepper, thyme and rosemary and cook until fragrant, about 1-2 minutes.

Step 4

Stir the flour into the vegetables and cook for 30 seconds then add the meat back into the pot and stir to combine.

Step 5

Gently pour in the beef stock, balsamic, worcestershire sauce, mustard and milk. Stir everything together and bring to a boil. Allow to cook until slightly thickened, about 3-5 minutes.

Step 6

Reduce the heat to low, add the lid and allow to simmer for 90 minutes or until the beef is tender and almost done.

Step 7

Remove the lid and allow to simmer for another 30 minutes until the beef is very tender and the sauce has reduced and thickened slightly.

Step 8

Add the peas and stir them into the meat mixture.

Step 9

Preheat the oven to 425 degrees. Spray a 9x13" casserole dish with nonstick spray and pour in the meat mixture.

Step 10

Unfold the sheet of puff pastry and make a few slits as vents in the top of the pie. Place the puff pastry on top of the filling. Whisk the egg wash of egg and milk together and brush gently over the puff pastry.

Step 11

Bake at 425 degrees for 30 minutes and enjoy!