Pre-heat oven to 425°F.
In a medium size skillet, heat the olive oil 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 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, 2-3 minutes.
Season with salt and pepper; remove from the heat.
Unroll the piecrusts and halve them. Divide the cooled meat among the four piecrust pieces, placing a mound on one 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.