Preheat the oven to 425 degrees . In a medium skillet, heat the EVOO over medium-high heat. Add the steak and cook until browned, 5 minutes. Transfer to a plate. Add the butter to the skillet to melt, then add the mushrooms and cook for 2 minutes. Add the onion and garlic and cook until softened, about 5 minutes. Sprinkle in the flour and cook, stirring, for 1 minute. Stir in the beef stock, peas and Worcestershire sauce. Return the meat to the pan and cook until the sauce thickens and the peas heat through, 2 to 3 minutes. Season with salt and pepper; remove from the heat.
Unroll the piecrusts and halve them. Divide the cooled meat among the 4 piecrust pieces, placing a mound on 1 side of each piece and leaving a small border. Brush the edges of each piecrust piece with some of the egg. Fold the pastry over to enclose the filling, pressing down on the edges; crimp with a fork. Brush the tops of the dough with more of the egg and transfer the pies to a parchment-lined baking sheet. Bake until golden-brown, about 10 minutes.