Preheat oven to 375°F (190°C). Grease a muffin tin with cooking spray.
Roll out 4 prepared pie crusts and using a 3-inch cookie cutter, cut out 6 circles from each pie crust.
Place the circles into the muffin tin and push each pie crust down into the bottom and up the sides.
Bake for 8-10 minutes. Remove the muffin tin from the oven and let cool while you prepare the filling.
To a large skillet, add the onion, garlic, and olive oil and sauté for 1-2 minutes.
Then add the ground beef and brown, breaking it up as it cooks. Drain any fat.
Add in the Worcestershire sauce, rosemary, thyme, salt, black pepper, tomato paste, and frozen veggies. Stir to combine.
Add the butter to the pan and melt. Sprinkle the flour over the meat and mix until well combined.
Add in the beef broth and let it simmer for about 5 minutes.
Add prepared mashed potatoes to a piping bag with a large round decorating tip.
Fill each pie crust with 1-2 tablespoons of the meat mixture and pipe on 1-2 tablespoons of mashed potatoes.
Broil for 8 minutes. Serve with fresh parsley.